The FAL Files  

Go Back   The FAL Files > Weapon Specific Forums > The FN Files

Notices

Reply
 
Thread Tools Display Modes
Old July 18, 2011, 05:37   #51
DakTo
MadMinuteDude
Platinum Contributor
 
DakTo's Avatar
 
FALaholic #: 9689
Join Date: Mar 2003
Location: Indian River, Florida
Posts: 8,111
"But it doesn't really end there. If you put your thinking caps on and extrapolate just a little bit, you realize that forged T-1 and cast T-3 aren't the only things to consider. We've also got several versions of forged T-3 receivers to choose from, and at the other end of the spectrum we have cast T-1's. Nobody as far as I know has ever ventured to guess where those items fall in the hierarchy of strength, durability, or whatever you wish to call it, so let me take a stab at it. I think any idiot could understand that the extra metal of a Type 3 receiver would make it stronger than the lightened Type 1 receiver no matter how it was formed or what it was made of. Another way of saying that would be that the lightening cuts of the Type 1 weaken the receiver to some extent, no matter how little. Apparently there was enough weakening to convince FN to leave just a bit of extra steel to make the Type 2."


Does the manufacturing process of the Type 3 receiver cut down on the machining time? Sure it does, but I still believe by not removing the metal on the rear section does infact better reinforce the receiver overall. I think this change in specifications played a duel role on FNs decision for the change.

Just ask yourself this question: Why was the Type 2 receiver developed? To cut down on machining time, the answer would be "No" as the process required an extra lightening cut. The rational of the Type 2 was to reduce metal fatigue most likely caused by the bolt buffering against the face of the lower receiver in the recoil area durine automatic firing.
By allowing the extra metal to be maintained on the Type 3 receiver it is logical to perceive that area of the receiver will maintain enhanced structural intigerty.

I would submit that the Type 1 receivers have failed more often versus the Type 3 by virtue of the numbers of Type 3s still in service.
Excellent post Kev and we seemingly have this same discussion at least once a year on this topic.
__________________
NEVER touch another man's fries.
DakTo is online now   Reply With Quote
Old July 18, 2011, 07:26   #52
Eric Bryant
Registered
 
Eric Bryant's Avatar
 
FALaholic #: 7670
Join Date: Oct 2002
Location: West MI
Posts: 2,180
Quote:
Originally posted by DakTo
Does the manufacturing process of the Type 3 receiver cut down on the machining time? Sure it does, but I still believe by not removing the metal on the rear section does infact better reinforce the receiver overall. I think this change in specifications played a duel role on FNs decision for the change.
Adding (or leaving) additional material in areas of lower stress can actually increase the amount of strain in areas of higher stress. It's not intuitive, but it's true.

Saying that something is weaker or stronger because of the absence or presence of additional material is usually just guesswork without doing the proper engineering analysis. In the case of something complex like a FAL receiver, about the only way to truly "prove" this would be extensive durability testing to failure, or finite element analysis.
__________________
We're the middle children of history, man. No purpose or place. We have no Great War. No Great Depression. Our Great War's a spiritual war... our Great Depression is our lives. We've all been raised on television to believe that one day we'd all be millionaires, and movie gods, and rock stars. But we won't. And we're slowly learning that fact. And we're very, very pissed off. - Tyler Durden
Eric Bryant is offline   Reply With Quote
Old July 18, 2011, 07:41   #53
CAM
Registered
 
FALaholic #: 63844
Join Date: Jul 2011
Location: Western Pennsylvania
Posts: 1
Good job Kev - a little out of the box thinking with common sense - I love it.
CAM is offline   Reply With Quote
Old July 18, 2011, 07:50   #54
DakTo
MadMinuteDude
Platinum Contributor
 
DakTo's Avatar
 
FALaholic #: 9689
Join Date: Mar 2003
Location: Indian River, Florida
Posts: 8,111
Quote:
Originally posted by Eric Bryant


Adding (or leaving) additional material in areas of lower stress can actually increase the amount of strain in areas of higher stress. It's not intuitive, but it's true.

Saying that something is weaker or stronger because of the absence or presence of additional material is usually just guesswork without doing the proper engineering analysis. In the case of something complex like a FAL receiver, about the only way to truly "prove" this would be extensive durability testing to failure, or finite element analysis.
Please elaborate on your analysis with scientific documentation which would support less hardened metal being more resistant to vibration.

Thank you.
__________________
NEVER touch another man's fries.
DakTo is online now   Reply With Quote
Old July 18, 2011, 08:31   #55
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
If you are up to a little lite reading Google (charpy v notch test) it will give you a good basis to start down this road
machanic is offline   Reply With Quote
Old July 18, 2011, 08:46   #56
DakTo
MadMinuteDude
Platinum Contributor
 
DakTo's Avatar
 
FALaholic #: 9689
Join Date: Mar 2003
Location: Indian River, Florida
Posts: 8,111
Quote:
Originally posted by machanic
If you are up to a little lite reading Google (charpy v notch test) it will give you a good basis to start down this road
The quantitative result of the impact tests the energy needed to fracture a material and can be used to measure the toughness of the material and the yield strength. Also, the strain rate may be studied and analyzed for its effect on fracture.
The testing are of all common metallic materials and not focused exclusively and directly on hardened material and perhaps a major disadvantage is that all results are only comparative.

Thanks for the information and good reading.
__________________
NEVER touch another man's fries.
DakTo is online now   Reply With Quote
Old July 18, 2011, 09:01   #57
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
A good chart if can find one is a drawdown or tempering chart with uses and resulting hardness,I have color, temp, use, but no hardness, it does show that tools such as punches and chisles (tools that indure repeated high impact) have a high draw temp= less hard condition than cutting tools which are harder but are prone to chip, fracture under impact
machanic is offline   Reply With Quote
Old July 18, 2011, 11:49   #58
kev
Old Fart
Contributor
 
kev's Avatar
 
FALaholic #: 71
Join Date: Jul 2000
Location: Indiana and various others
Posts: 5,152
The engineering theory and destructive testing is fine for the engineers, but I'll take my assumptions based on 50yrs of manufacturing evolution thank-you-very-much. The forged T-2 was the epitome of FN manufacture,................anything that came after was driven by cost cutting efforts to keep the FAL in the game and was an admittedly inferior receiver. The forged T-3 was only made possible by the reduced manufacturing costs of the southern hemisphere(FN certainly could have gone there, but they skipped that step and doubled up on the cost-cutting, going straight to the cast T-3).

US commercial production receivers? Really? Their ONLY concern is knocking them out as cheaply as possible and sending them down the road. They know that you're not likely to pass the ten thousand round mark in your(or their)lifetime. Why build to a standard that won't be appreciated(or paid for)? With DSA as the only exception, look at what has been manufactured here,......................Hesse(cast), Century(cast), Olympic(cast), DPMS(cast), Entreprise(cast,..........with early bar stock?), Coonan(current cast and the earlier FAC cast). Hey, put the WAC in here too. It was fully machined(from bar stock most certainly), but their shot at cost reduction was to machine from aluminum which is a much less costly process.

You might arguably be able to list the DSA receivers up with the FN T-1, T-2, South American T-3's, and all the military production receivers, but that's where the door slams shut. Everything else is an also-ran, not that there aren't some good receivers in that lot. I particularly like and recommend the Coonans(although I'm going to stick to the T-3's generally and treat them lightly,.............'cause I want to; not necessarily because I have to). I'm not going to run 100,000rds through anything. But that wasn't the question. The question seemed to be "Is a forged receiver 'better' than a cast receiver?" and the answer is yes. If you want to argue that some imaginary poorly forged receiver might possibly be less better than a phenominally well cast receiver or that that same poorly forged receiver might not hold up as well as a cast fan blade, go on,......................I'll watch.

OTOH, if the real question is "Does it matter in my semi-auto FAL?", then that's not quite so clear cut. Depends on whether it matters to you. I'm generally fine with a cast receiver, but when someone claims that a cast T-1 will run with something like an Imbel or Argy and that there's no difference,.................someone's not thinking clearly. There's a difference; only you can decide whether that difference matters.

I've been sensing a trend here lately while following the Entreprise Type-1 receiver fiasco and drifting into the Coonan Type-1 offering. I'm sure the Coonan is going to be a good receiver. They've done this before(the old FAC was a Coonan)and Coonan has always been good people and they produce a quality product. The Entreprise 'fiasco' was mostly Entreprise being Entreprise,..........inconsistent QC, unrealized promises and hit-or-miss customer support. Not necessarily a 'receiver problem' but more of a 'company problem'. Still, IMHO, offering a cast T-1 is economically giving the customer what he thinks he wants based mostly on said customer not knowing much. That might be OK business, but it seems like poor customer thinking to me.

I guess what I'm trying to say is that if/when guys start tearing down good rifles built up on Imbel receivers so that they can replace them with new cast Type 1's out of some weird sense of style or 'correctness', I'm not going to be the one to offer support. I'll be the one suggesting they go repaint the dining room and shop for matching window dressing. Maybe let the wife or girlfriend handle the weapons squad for awhile. But if that's where you're gonna go, please let me know. I can always use a few more cast-off Imbels.

*Entirely my opinion based on implied facts and guesswork and offered as such*
__________________
Gun control is not about guns; it's about control.

RUE?
kev is offline   Reply With Quote
Old July 18, 2011, 13:43   #59
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
The original question as I understand it was WHY a forged receiver is superior to a cast receiver, throwing out cost, politics of the frount office of a manufacturer, and if a Fal even needs the the added strength, so it would be more of an engineering/metalergist question on the reasons why a forging is superior to a casting. Pardon my spelling I was not an English major!
machanic is offline   Reply With Quote
Old July 18, 2011, 13:59   #60
4markk
Military Observer
Gold Contributor
 
4markk's Avatar
 
FALaholic #: 31134
Join Date: Aug 2007
Location: Army of Occupation of Northern Virginia
Posts: 5,014
Kev,

I understand your thinking and agree with some of your analysis and some of your conclusion. First of all, I will concede that "forged" is stronger. But what this question always seems to come down to, is "Good-Enough" good enough? Allow me to give you my opinion.

My first observation (and point of contention) is that FN experiments were conducted under conditions that are mostly not valid today. They were set for a military application of a full-automatic rifle. Fatigue was studied using the extreme conditions of that rifle in that military application (i.e. sustained full-automatic fire). Tension and compression stresses are less predictable in repetitive or fluctuating application of load. A general axiom of metal fatigue states, "metal subjected to a repetitive or fluctuating stress will fail at a stress much lower than that required to cause fracture on a single application of load." You combine that with the extreme temperatures and vibrations (harmonics, collisions, etc ...) experienced in sustained auto-fire that are not achievable in semi-fire and your results are even more skewed. In other words, using one to predict the other is invalid. At best case, it will be a general rough (maybe close) estimate of economic life.

So then we are down to, is "Good-Enough" good enough? First of all, considering the audience, we are FALaholics because we love the feel of that cold heavy solid over-engineered battle rifle. A good portion us will not touch the stamped steel commie-crap unless we are prying it from the cold dead hands of the terrorist that tried to wield it against us. So I set the condition: For us the more solid the better.

Setting the rifle aside for moment; does it make sense to pay twice as much for a TV that has a resolution incapable to be seen by the human eye then for one that is at or near the max capability of the human eye? Now pick up the rifle; does it make sense to avoid a receiver that will outlive you and probably your children just because another one is stronger? How you answer that question will greatly steer which receiver you will purchase. Not from an engineering perspective or from an application perspective but solely from a feeling of want. No different than the other person's want of cosmetic features.

Of course in my most humble opinion !!!!!
__________________
`
`
The difference between the possible and the impossible is only in the degree of a man's will. Chinese Proverb

“The worst thing about growing old is that other men stop seeing you as dangerous.” Act Of Valor

"A wise man gets more use from his enemies than a fool from his friends." Socrates
4markk is online now   Reply With Quote
Old July 18, 2011, 14:20   #61
Eric Bryant
Registered
 
Eric Bryant's Avatar
 
FALaholic #: 7670
Join Date: Oct 2002
Location: West MI
Posts: 2,180
Quote:
Originally posted by DakTo
Please elaborate on your analysis with scientific documentation which would support less hardened metal being more resistant to vibration.
Go take a look at an automotive leaf spring, or a fishing pole, or an airplane wing, or a typical rifle barrel profile. The taper that is present in each of these designs are excellent examples of "less is more". You would also observe the same principle if you were to cut a cross-section of tubing in a high-end steel or aluminum bicycle frame. Nature also provides evidence of this almost everywhere; tree limbs offer a particularly good example.

When designing a structure, you don't just lump on as much material as you can. Ideally, a structure is designed such that under a given load, the strain (deflection) of the material is equalized throughout the part. If you take a design that has been optimized in such a fashion and then make a portion of it stiffer by adding more material (such as your example of the extra material in a T3 compared to a T2), then you will likely make the structure stiffer overall. But you would also likely decrease the cyclical life of the structure by making the material in the untouched portion subject to more strain, which is detrimental to fatigue strength.

Additional "scientific documentation" can be found at your local university in the mechanical engineering program.
__________________
We're the middle children of history, man. No purpose or place. We have no Great War. No Great Depression. Our Great War's a spiritual war... our Great Depression is our lives. We've all been raised on television to believe that one day we'd all be millionaires, and movie gods, and rock stars. But we won't. And we're slowly learning that fact. And we're very, very pissed off. - Tyler Durden
Eric Bryant is offline   Reply With Quote
Old July 18, 2011, 14:21   #62
nwobhm
ΜΟΛΩΝ ΛΑΒΕ
 
nwobhm's Avatar
 
FALaholic #: 9580
Join Date: Feb 2003
Location: USA
Posts: 9,063
Quote:
Originally posted by 4markk
does it make sense to avoid a receiver that will outlive you and probably your children just because another one is stronger?
The stronger one costs $50 more. That's $50 more to double the life expectancy of the most expensive part on the gun. That aside... What if surplus becomes cheap again? Say .15 per round. Low ammo cost will equal more trigger time. If forged were $600 and cast were $225 cost would be important... but for $50.... Forged hands down.
nwobhm is offline   Reply With Quote
Old July 18, 2011, 14:23   #63
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
Well said by the way if you go to the range twice a month with your favorite gun shoot 200rds. =4800 rds 1 year/ 4 years????????

Last edited by machanic; July 18, 2011 at 14:31.
machanic is offline   Reply With Quote
Old July 18, 2011, 14:41   #64
indy_Muaddib
Curio & Relic
Bronze Contributor
 
indy_Muaddib's Avatar
 
FALaholic #: 17581
Join Date: May 2005
Location: Tampa FL
Posts: 3,099
are people actually using the "it costs more so it must be better" argument?

find me a forged receiver for $350 or less and ill buy it, til then its coonan for me.

or invest in my time machine project so i can go back 15 years and buy all the imbel GL receivers for $200 and bring them back to now.
__________________
When the government violates the people's rights, insurrection is, for the people and for each portion of the people, the most sacred of the rights and the most indispensable of duties.

-Gilbert du Motier, marquis de Lafayette 1790
indy_Muaddib is offline   Reply With Quote
Old July 18, 2011, 14:48   #65
nwobhm
ΜΟΛΩΝ ΛΑΒΕ
 
nwobhm's Avatar
 
FALaholic #: 9580
Join Date: Feb 2003
Location: USA
Posts: 9,063
Quote:
Originally posted by indy_Muaddib


find me a forged receiver for $350 or less and ill buy it, til then its coonan for me.

Call 1-847-277-7258. DS Arms, falfiles discount is $350.
nwobhm is offline   Reply With Quote
Old July 18, 2011, 14:55   #66
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
The joy of low price is soon forgottin, as the bitterness of poor quality lingers!!
Butcher shop wall
machanic is offline   Reply With Quote
Old July 18, 2011, 15:45   #67
DakTo
MadMinuteDude
Platinum Contributor
 
DakTo's Avatar
 
FALaholic #: 9689
Join Date: Mar 2003
Location: Indian River, Florida
Posts: 8,111
Quote:
Originally posted by kev
The engineering theory and destructive testing is fine for the engineers, but I'll take my assumptions based on 50yrs of manufacturing evolution thank-you-very-much. The forged T-2 was the epitome of FN manufacture,................anything that came after was driven by cost cutting efforts to keep the FAL in the game and was an admittedly inferior receiver. The forged T-3 was only made possible by the reduced manufacturing costs of the southern hemisphere(FN certainly could have gone there, but they skipped that step and doubled up on the cost-cutting, going straight to the cast T-3).

US commercial production receivers? Really? Their ONLY concern is knocking them out as cheaply as possible and sending them down the road. They know that you're not likely to pass the ten thousand round mark in your(or their)lifetime. Why build to a standard that won't be appreciated(or paid for)? With DSA as the only exception, look at what has been manufactured here,......................Hesse(cast), Century(cast), Olympic(cast), DPMS(cast), Entreprise(cast,..........with early bar stock?), Coonan(current cast and the earlier FAC cast). Hey, put the WAC in here too. It was fully machined(from bar stock most certainly), but their shot at cost reduction was to machine from aluminum which is a much less costly process.

You might arguably be able to list the DSA receivers up with the FN T-1, T-2, South American T-3's, and all the military production receivers, but that's where the door slams shut. Everything else is an also-ran, not that there aren't some good receivers in that lot. I particularly like and recommend the Coonans(although I'm going to stick to the T-3's generally and treat them lightly,.............'cause I want to; not necessarily because I have to). I'm not going to run 100,000rds through anything. But that wasn't the question. The question seemed to be "Is a forged receiver 'better' than a cast receiver?" and the answer is yes. If you want to argue that some imaginary poorly forged receiver might possibly be less better than a phenominally well cast receiver or that that same poorly forged receiver might not hold up as well as a cast fan blade, go on,......................I'll watch.

OTOH, if the real question is "Does it matter in my semi-auto FAL?", then that's not quite so clear cut. Depends on whether it matters to you. I'm generally fine with a cast receiver, but when someone claims that a cast T-1 will run with something like an Imbel or Argy and that there's no difference,.................someone's not thinking clearly. There's a difference; only you can decide whether that difference matters.

I've been sensing a trend here lately while following the Entreprise Type-1 receiver fiasco and drifting into the Coonan Type-1 offering. I'm sure the Coonan is going to be a good receiver. They've done this before(the old FAC was a Coonan)and Coonan has always been good people and they produce a quality product. The Entreprise 'fiasco' was mostly Entreprise being Entreprise,..........inconsistent QC, unrealized promises and hit-or-miss customer support. Not necessarily a 'receiver problem' but more of a 'company problem'. Still, IMHO, offering a cast T-1 is economically giving the customer what he thinks he wants based mostly on said customer not knowing much. That might be OK business, but it seems like poor customer thinking to me.

I guess what I'm trying to say is that if/when guys start tearing down good rifles built up on Imbel receivers so that they can replace them with new cast Type 1's out of some weird sense of style or 'correctness', I'm not going to be the one to offer support. I'll be the one suggesting they go repaint the dining room and shop for matching window dressing. Maybe let the wife or girlfriend handle the weapons squad for awhile. But if that's where you're gonna go, please let me know. I can always use a few more cast-off Imbels.

*Entirely my opinion based on implied facts and guesswork and offered as such*
You opinion is well noted, however I question why countries as Argentina, Brazil and other FN licensees did not choose to retain manufacturing the original Type 1 receiver and progress to the Type 3 receiver. These countries employed larger military and civilian forces and would not it be in their best interest to provide their troops and civilian market with the top of the line hardware?

There was an estimated 2 Million plus total types of FALs manufactured and all receivers which cracked or flaked were most likely negligible as a percentage of manufactured completed FALs. Notwithstanding, I have not read a report of Type 3 receivers cracking or flaking, but have read and understood the reasoning why FN changed from a Type 1 to the Type 2 which is common knowledge.

Let's understand the FN military market and the current domestic market on receivers is like apple & oranges, although I must give kudos to DSA as they do cater and supply government contracts so perhaps their receiver need to be the most efficient on the market. The military like to test the crap out of hardware before purchasing in most cases.
I agree from a civilian perspective the argument of forged versus cast is a bit overrated as most of us will not pass through 20,000 rounds less afford to spend that kind of funds in today's inflationary world.
__________________
NEVER touch another man's fries.
DakTo is online now   Reply With Quote
Old July 18, 2011, 16:42   #68
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
You people are off track again, The question was is a forged better than a cast and why,,, not if you need one or if one is nessissary!!!!!!!!! OH and buy the way At one time in my life I used to shoot 22 compitition, a 5000 rdn brick was a months supply, in 5 years I burn't out two actions and three barrels and these where bolt action, and I wasn't exceptional on the team,, OK it's 22 and verry cheep but it does happen!!!
machanic is offline   Reply With Quote
Old July 18, 2011, 19:31   #69
4markk
Military Observer
Gold Contributor
 
4markk's Avatar
 
FALaholic #: 31134
Join Date: Aug 2007
Location: Army of Occupation of Northern Virginia
Posts: 5,014
Quote:
Originally posted by nwobhm


The stronger one costs $50 more. That's $50 more to double the life expectancy of the most expensive part on the gun. That aside... What if surplus becomes cheap again? Say .15 per round. Low ammo cost will equal more trigger time. If forged were $600 and cast were $225 cost would be important... but for $50.... Forged hands down.

Understood, but did you get what you wanted? If you did, that is a good deal.

There are over 60,000 members of this forum. How many have burnt out a in-spec cast receiver (means not counting late model Entreprise, Hesse, or Alumibombs)?

So is cast "Good-Enough"?
__________________
`
`
The difference between the possible and the impossible is only in the degree of a man's will. Chinese Proverb

“The worst thing about growing old is that other men stop seeing you as dangerous.” Act Of Valor

"A wise man gets more use from his enemies than a fool from his friends." Socrates
4markk is online now   Reply With Quote
Old July 18, 2011, 20:19   #70
nwobhm
ΜΟΛΩΝ ΛΑΒΕ
 
nwobhm's Avatar
 
FALaholic #: 9580
Join Date: Feb 2003
Location: USA
Posts: 9,063
Quote:
Originally posted by 4markk



Understood, but did you get what you wanted? If you did, that is a good deal.

There are over 60,000 members of this forum. How many have burnt out a in-spec cast receiver (means not counting late model Entreprise, Hesse, or Alumibombs)?

So is cast "Good-Enough"?
IMHO no.
nwobhm is offline   Reply With Quote
Old July 19, 2011, 04:03   #71
kev
Old Fart
Contributor
 
kev's Avatar
 
FALaholic #: 71
Join Date: Jul 2000
Location: Indiana and various others
Posts: 5,152
Quote:
Originally posted by DakTo


You opinion is well noted, however I question why countries as Argentina, Brazil and other FN licensees did not choose to retain manufacturing the original Type 1 receiver and progress to the Type 3 receiver. These countries employed larger military and civilian forces and would not it be in their best interest to provide their troops and civilian market with the top of the line hardware?
You're misunderstanding me or I'm misunderstanding you. Sometimes I think faster than I type and I skip a few steps. The Type 2 was the best receiver FN ever made. When they went to the Type 3 they also went with the casting, so they in effect doubled up on the cost-cutting with both a cheaper method of manufacture and less machining to finished product.

The Brazilians and Argentines saved some machine time by going to the Type 3 profile, but they stuck with forgings. They saved a bit of manufacturing expense but did not diminish the quality of the product. I commend them for that. I did not mean to imply that they were inferior to the FN Type 2. I meant that they were superior to the FN Type 3. I believe the South American Type 3's are top of the line.
__________________
Gun control is not about guns; it's about control.

RUE?
kev is offline   Reply With Quote
Old July 19, 2011, 17:26   #72
chrsdwns
Registered
 
FALaholic #: 9846
Join Date: Mar 2003
Location: USA
Posts: 2,710
An interesting and informative comparison from Rexnord Corp between forged and cast 4140/4135 series steel for power transmission components.

Power transmission (gears ect) components are subject to combinations of cyclic fatigue, shock loading and surface wear due to metal to metal sliding contact so this discussion and comparison is reasonably applicable and relevant to FAL receivers. One caveat - this paper mentions that it is primarily applicable to large parts but does not discuss in any detail the assumptions of what constitutes a large part or how(or if) the data is specialized to a large part. The tensile numbers would suggest a heat treat to about Rc 42- 45 which is a bit higher than than the Rc 35-38 DSA or Coonan uses on their receivers.

http://pt.rexnord.com/customer_suppo...perdbl_col.asp

FWIW, cast test specimens performed very well and actually out performed forged test specimens in notched cyclic fatigue, which is a good simulation of the FAL receiver. How this translated into real world practice is unclear but obviously a - properly made - cast part out of 4140 steel is a very viable option for a quality FAL receiver. I was actually kind of surprised at how well the cast tests went.

What it really comes down to is consistently high quality throughout the manufacturing process. A well done cast receiver is better than a poorly done forged receiver and well done forged receiver is better than a poorly done cast receiver.

A well done forged receiver may or may not be better than a well done cast receiver. It all comes down to detail design and quality control of the part and manufacturing process and how well the complex state of stress in the part interacts with the anisotropic mechanical properties of the forged part compared to the more isotropic properties of the cast component along with significance of notch sensitivity and now the notches of the part are oriented with respect to the direction of the grain structure of the forging and direction of the applied loads.

The FAL receiver has extensive examples of notches in critical, highly loaded areas. One significant area of multiple notches is the locking shoulder area. The locking shoulder area of the FAL receiver sees high loads and a complex state of stress. I always slightly radius, smooth and polish the locking shoulder holes in the receiver on general principals during a FAL build for this reason. It's probably a waste of time but old habits of good practices die hard.

When is comes to wear, both the DSA and the Coonan should be much better than the FN forged or cast high carbon steel receivers because the fully hardened 4130 alloy used in both the DSA and Coonan receivers is much more wear resistant than the unhardened high carbon steel used for the ways of the of the FN receiver.

4130 is also a more corrosion resistant steel alloy alloy than high carbon content mild steel.

Dan Coonan was a pioneer of and is very knowledgeable at investment casting for firearm applications so I think it is reasonable to assume that he is having the raw castings done correctly


IMHO, DSA still makes the best FAL receiver ever made
__________________
"Those who do not move do not notice their chains. " -Rosa Luxumberg

"There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as a result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved."
~~Ludwig Von Mises

...when poets buy guns, tourist season is over................Walter R. Mead.

Last edited by chrsdwns; July 19, 2011 at 17:58.
chrsdwns is offline   Reply With Quote
Old July 19, 2011, 19:10   #73
jbrooks
Registered
 
FALaholic #: 10395
Join Date: Apr 2003
Posts: 1,731
Quote:
Originally posted by chrsdwns
An interesting and informative comparison...
chrsdwns,

Finally a clear and definitive engineering statement worthy of this sticky.

This is the kind of analyisis I like to see.

Your treatmnet of sharp corners in the locking lug area is precisely consistent with for example, the USGI requirement for specific radii at corners in the M14 design. An example is the radius spec for the M14 bolt locking lugs at the lug roots. Which is why some commercial bolts fail.

The bottom lines you mention speak for themselves.

Thanks!

JWB
jbrooks is offline   Reply With Quote
Old July 20, 2011, 06:59   #74
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
One slight problem the report starts off with (Heavy sections will be interepeted to mean parts in excess of 10 tons and minumin metal section of 200 mm(5") a little out of receiver specs!!!
machanic is offline   Reply With Quote
Old July 20, 2011, 07:12   #75
Tim Dreas
Registered
 
FALaholic #: 17255
Join Date: Apr 2005
Location: York,PA
Posts: 891
Steel used in investment castings differ in usually having a higher silicon content to allow better flow / fill in the molds. For example 4140 made for investment castings is called "4140-C." When FN changed from forged receivers to investment cast receivers FN then also "upgraded" the steel from a steel similar to American 1060 used in the forged receivers to a steel similar to American 4140 steel for the investment cast receivers. Leaving out the differences in forgings and investment castings, 4140 should be a tougher, stronger steel than 1060. It's not just comparing forging and ivestment casting but also the different steels used.n
__________________
http://www.mpri.com/
Tim Dreas is offline   Reply With Quote
Old July 20, 2011, 09:42   #76
Eric Bryant
Registered
 
Eric Bryant's Avatar
 
FALaholic #: 7670
Join Date: Oct 2002
Location: West MI
Posts: 2,180
Quote:
Originally posted by machanic
One slight problem the report starts off with (Heavy sections will be interepeted to mean parts in excess of 10 tons and minumin metal section of 200 mm(5") a little out of receiver specs!!!
How is that a problem? Does each crystal of steel know that it is in a big piece or a small piece, and thus changes its behavior accordingly?
__________________
We're the middle children of history, man. No purpose or place. We have no Great War. No Great Depression. Our Great War's a spiritual war... our Great Depression is our lives. We've all been raised on television to believe that one day we'd all be millionaires, and movie gods, and rock stars. But we won't. And we're slowly learning that fact. And we're very, very pissed off. - Tyler Durden
Eric Bryant is offline   Reply With Quote
Old July 20, 2011, 17:46   #77
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
No metal to the best of my knowledge is not sentiant! It's just that large verses small have very different inertia forces, second and third derivitives, acceleration and jerk(rate of change of acceleration) which changes peak forces and preassures for a given area. Try cycling a 10 ton gear back and forth at 600cpm like a bolt at full auto and see what happens!! Casting are much more ridgid than forgings and work better on large machines where flex of a few ths.per in. add up to severe misalignment on parts and accelerated wear.
machanic is offline   Reply With Quote
Old July 21, 2011, 06:51   #78
DakTo
MadMinuteDude
Platinum Contributor
 
DakTo's Avatar
 
FALaholic #: 9689
Join Date: Mar 2003
Location: Indian River, Florida
Posts: 8,111
An opinion I picked up off another site...

"Cast vs forged is a very iffy issue. A forging is almost always more expensive because it's labor intensive and time consuming but the forging process is not always without it's limitations. A casting tends to be more "uniform' in its composition and goes through fewer processes to reach its final stage, less chance for error. Also their are certain alloys (and their desirable properties) that cannot go through the forging process well if at all. If a manufacturer is willing to pay the money, there is little to be gained from a forging that can't be equalled or bettered by a casting. For years I worked with cast steel products that would routinely exceed 110,000 psi, they replaced the forged products that were only rated at 75,000 psi and they did it cheaper and faster. Its called science and progress."
__________________
NEVER touch another man's fries.
DakTo is online now   Reply With Quote
Old July 21, 2011, 07:16   #79
Eric Bryant
Registered
 
Eric Bryant's Avatar
 
FALaholic #: 7670
Join Date: Oct 2002
Location: West MI
Posts: 2,180
machanic,

All those factors you mentioned are interesting and might serve to throw up a smoke screen for someone else, but at the end of the day, they just contribute to stress and strain.

Castings are not more rigid than forgings. Cast steel has the same modulus (stiffness) as forged steel (all steels have pretty much the same modulus, regardless of composition, hardening, or fabrication method). Grey cast iron is actually quite flexible, with a modulus less than brass or CP titanium. Don't mistake a lack of ductility for a high modulus.
__________________
We're the middle children of history, man. No purpose or place. We have no Great War. No Great Depression. Our Great War's a spiritual war... our Great Depression is our lives. We've all been raised on television to believe that one day we'd all be millionaires, and movie gods, and rock stars. But we won't. And we're slowly learning that fact. And we're very, very pissed off. - Tyler Durden
Eric Bryant is offline   Reply With Quote
Old July 21, 2011, 18:21   #80
Rahatlakhoom
Registered
 
Rahatlakhoom's Avatar
 
FALaholic #: 25271
Join Date: Jan 2007
Location: Indiana
Posts: 616
shoot the rifle.
Rahatlakhoom is offline   Reply With Quote
Old July 21, 2011, 18:53   #81
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
when someone makes a coilspring from cast steel I'll agree, castings will then equil forgings, till then the gap is closing but is not closed
machanic is offline   Reply With Quote
Old July 22, 2011, 13:00   #82
newtown
Registered
 
FALaholic #: 28250
Join Date: Apr 2007
Location: MN
Posts: 136
Since we are on the subject. again....

Coonan receivers are investment cast, thick, heat treated, then machined.

We have never had one returned worn out.

Coonan Engineered for Todays FAL!

Also while I am here we have FAL T-shirts.



http://www.coonaninc.com/index.php/cPath,8
newtown is offline   Reply With Quote
Old July 23, 2011, 07:29   #83
Eric Bryant
Registered
 
Eric Bryant's Avatar
 
FALaholic #: 7670
Join Date: Oct 2002
Location: West MI
Posts: 2,180
Quote:
Originally posted by machanic
when someone makes a coilspring from cast steel I'll agree, castings will then equil forgings, till then the gap is closing but is not closed
Coil springs are not forged (they are worked from drawn wire), and their usage profile is much different than a firearm receiver (tens of thousands of cycles versus hundreds of millions - call it five orders of magnitude). Either you do not know the difference and thus are not qualified to speak to this issue, or you do know the difference and are not being honest. Which is it?

In the meantime, I suggest you stay away from automobiles, bridges, tall buildings, several brands of handguns, and any number of hand or power tools. You can never be too safe in avoiding highly-stressed cast steel, right?
__________________
We're the middle children of history, man. No purpose or place. We have no Great War. No Great Depression. Our Great War's a spiritual war... our Great Depression is our lives. We've all been raised on television to believe that one day we'd all be millionaires, and movie gods, and rock stars. But we won't. And we're slowly learning that fact. And we're very, very pissed off. - Tyler Durden
Eric Bryant is offline   Reply With Quote
Old July 23, 2011, 15:45   #84
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
Didn't think I had to go back to Manufacturing Processes 101!!
From Wikipedia forgings
Processes
There are many different kinds of forging processes available, however they can be grouped into three main classes
Drawn out: length increases cross-section decreases (WIRE FORMING)
Upset: length decreases cross-section increases (train wheels)
Squeezed in closed compression dies: produces multidirectional flow ( ever have a end sweged onto a cable? also complex shapes, gun parts)
as to your other comments, except for the hand gun, none of the mention have highly stressed parts, low stressed, moderate at most, and I like my 1911s with investment cast frames, but I stay away from +P loads.
All metal forming that does not involve cutting or metal removal boils down to two processes forging and casting, in casting the metal is liquid NO GRAIN STRUCTURE, as the metal solidifies grains forms, in forging cold or hot, grain structure is present and modified by the process, which is the reason for an increase in strength and ductility.
P.S. I sence a little attitude and hostility, there is no room for this in engineering, facts and math are the only tools, attutude and opinion are the relms of politicions and I have no use for their kind!!

Last edited by machanic; July 23, 2011 at 20:14.
machanic is offline   Reply With Quote
Old July 23, 2011, 20:48   #85
Sampson1986
Renegade
Contributor
 
FALaholic #: 43374
Join Date: Mar 2009
Location: Montana, USA
Posts: 1,123
Quote:
Originally posted by newtown
Coonan receivers are investment cast, thick, heat treated, then machined.

We have never had one returned worn out.
Is there any chance of getting Coonan to do a very limited run of Type 2 receivers?
__________________
RENEGADE: an individual who rejects lawful or conventional behavior.
Sampson1986 is offline   Reply With Quote
Old July 24, 2011, 12:07   #86
LaConservationist
Registered
 
LaConservationist's Avatar
 
FALaholic #: 42319
Join Date: Feb 2009
Location: South Louisiana Bayous!
Posts: 7,060
Quote:
Originally posted by HD Bee
BTW, what happened to the OP?
He seems to have stirred the pot and left.

[IMG][/IMG]

NOT at all HD, I asked the question that I wasn't sure of the answer to (as far as specifics and details,) I have been reading EVERY post! In my opinion some valid, some are just a pile of BS!

I have read enough to know just as I personally felt in the beginning, I will put one of my COONAN CAST RECEIVER built rifles against one of my DSA FORGED RECEIVER built rifles ANY DAY of the week!

Just as Kev's data shows below.....
Forged Type 3,.........120,000rds? (a guess?)
Forged Type 2,.........100,000rds? (a guess?)
Forged Type 1,...........80,000rds (per FN)
Cast Type 3,..............40,000rds (per FN)
Cast Type 1,..............20,000rds? (a guess?)

With these round counts this is calculated with FULL AUTO?
So just for Ghits and Siggles with a rifle used strickly in the semi auto configuration, mostly stored in a climate controlled safe or room, never used to pound someones head, never used as an AXE or a sledge hammer, cleaned and cared for somewhat often, at the VERY VERY MOST, what do you guys shoot in an average year, "GO HIGH" don't hold back.....hell be honest and add 500 rounds if ya dare! What 2000 rounds? (haha yeah maybe 10 out of 100 of us)
So lets revisit this in 10 years! We shall count the RECEIVER failures!

As for myself! I will shoot the piss out of my Coonan's (Early and Late models)just as my Imbel's and DSA's and NEVER worry about a STRUCTURAL FAILURE on EITHER of them!

While I am at it, I would be interested to see just how many of us will shoot 10,000 rounds (Thru the same rifle) in ten years!

OK wake up and face reality guys! Forged or Cast receivers from DSA, FMAP, IMBEL, COONAN........IT is going to OUT LIVE YOU!! PERIOD!!



Quote:
Originally posted by kev

If that all makes sense, lets throw some totally unproven guesses into a list and see where we might end up,.........

Forged Type 3,.........120,000rds? (a guess?)
Forged Type 2,.........100,000rds? (a guess?)
Forged Type 1,...........80,000rds (per FN)
Cast Type 3,..............40,000rds (per FN)
Cast Type 1,..............20,000rds? (a guess?)

The expected round count might be fairly accurate or it might be wildly inaccurate, but I have absolutely no doubt that the ranking is correct and that the differences are more than merely measurable.

I don't expect to ever wear out an FAL receiver of any type, but that's mostly because I think I understand their limits and I don't plan on exceeding any of them. But I do expect to be around to hear about other people's problems with them in the future.
Kev, with all due respect THANK you for the detailed insight you have taken the time to enter here, my only real disagreement is that I do NOT belive any of us will be around to see failures of ANY of these receivers due to CAST vs. forged, yeah maybe due to some bubba doing UNHEARD of things to their rifle.....maybe some idiot firing a rifle without a locking shoulder.....sure we will read about failures, but as far as "WEARING OUT" a receiver because receiver one was cast and receiver two was forged??? I don't think we know anyone that will EVER burn that much ammo in a semi auto rifle!!

OK there is my opinion!!

THANKS GUYS!!

LaC
__________________
In MEMORY of Roger "DUNKRD" Dunkelbarger September 13, 1943 - May 09, 2010

"Any one who thinks he can be happy
and prosperous by letting
the Government take care of him,
better take a closer look at the American Indian."

- Henry Ford

Last edited by LaConservationist; July 24, 2011 at 12:14.
LaConservationist is offline   Reply With Quote
Old July 24, 2011, 15:25   #87
Matt(formerly@)EntrepriseArms
Registered
 
Matt(formerly@)EntrepriseArms's Avatar
 
FALaholic #: 32036
Join Date: Oct 2007
Location: CA
Posts: 469
I'll offer my $.02 on a couple of subjects brought up here:

Blueprints - everybody touts DSA for using "original" blue prints, and says everybody reverse engineers their receivers. Entreprise has "original" blue prints too, where and from whom they obtained them - I have no idea as it was years before I ever worked there. I know they used them as the starting point to make their receiver, and then used Imbles that they imported for dimension and function comparison and testing. Does DSA acutally have the "original" Steyr blueprints? I don't know, as I've never seen them. As I've pointed out before, the "true" blue prints are the ones the machinest used with all of his notations drawn on it with the changes he had to make.

We we brought out the Brit cut L1A1, we obtained blue prints from a forum member, and were offered prints from several other people as well. All of these prints were the generic ones, and not an actual one hanging on the wall in Birmingham (that is from what I saw, but since we did not take them from everybody who offered them, I can't say that one of theirs was not the "original).

I have no idea how Coonan or Century designed their receivers as I've never personally asked them.

I take the whole blueprints vs reverse engineered thing with a grain of salt.

Cast vs. forged - everybody knows forged is harder and "stronger" for some intents and purposes, and casting is softer and has the potential for porosity. Whether one lasts longer than the other or one is "safer" than the other requires what someone mentioned above - a torture test. Otherwise, its all just speculation as we won't know the true result until then.

As far as the casting go, people make general statements and assumptions that Entreprise's is crappier somehow with no factual basis to make those claims. Entreprise currently buys their casting from this company: http://www.fenicocastings.com/

Perhaps you can ask Coonan where they buy their's, and somebody can try to decide which casting company is "better."

Personally, I own three Entreprise Fals, and I am very happy with them. I have no fear of them blowing up in my face, and as far as I know in the history of the company, only two receivers have cracked and in both cases the owner admitted to using reloads.

During the time I worked there, and from what I was told, no one ever "wore out" their receiver and returned it.

I can't speak for any other company and if they have ever had one of their receivers crack or not, but thats what I know about Entreprise.
Matt(formerly@)EntrepriseArms is offline   Reply With Quote
Old July 24, 2011, 20:33   #88
Eric Bryant
Registered
 
Eric Bryant's Avatar
 
FALaholic #: 7670
Join Date: Oct 2002
Location: West MI
Posts: 2,180
Quote:
Originally posted by machanic
Didn't think I had to go back to Manufacturing Processes 101!!
No, I think you need to go back to Mechanics of Materials (assuming that you ever took such a class). While you are there, punch your prof in the face for doing such a crappy job of educating you the first time around.

Quote:
as to your other comments, except for the hand gun, none of the mention have highly stressed parts, low stressed, moderate at most, and I like my 1911s with investment cast frames, but I stay away from +P loads.
Really?!? There are far more people here who have broken car parts or tools than there are who have blown up firearms, and that says a lot about the stress level present within the part. Just because there is a violent combustion event within a firearm does not mean that it is automatically the most highly-stressed structure in the world.

You seem to be confusing the concept of stress with the concept of force, and ignore the influence of geometry, cross-sections, and load paths. How much structural analysis work have you performed?

Quote:
in forging cold or hot, grain structure is present and modified by the process, which is the reason for an increase in strength and ductility.
That's fine for a component with minimal post-forging machine work, but what happens when literally every surface is affected by a series of deep machining operations? What do you think that might do to the grain structure?

Quote:
P.S. I sence a little attitude and hostility, there is no room for this in engineering, facts and math are the only tools, attutude and opinion are the relms of politicions and I have no use for their kind!!
I have little patience for those that make repeated errors in a field which they claim to have proficiency - especially when that field is my own.
__________________
We're the middle children of history, man. No purpose or place. We have no Great War. No Great Depression. Our Great War's a spiritual war... our Great Depression is our lives. We've all been raised on television to believe that one day we'd all be millionaires, and movie gods, and rock stars. But we won't. And we're slowly learning that fact. And we're very, very pissed off. - Tyler Durden
Eric Bryant is offline   Reply With Quote
Old July 26, 2011, 13:40   #89
machanic
Member
Contributor
 
FALaholic #: 63516
Join Date: May 2011
Location: R.I.
Posts: 233
www.forging.org/facts/faq9.cfm for those who don't know what constitutes a forging reference post #93
pay close attention to ( cold forging )

Last edited by machanic; July 26, 2011 at 13:49.
machanic is offline   Reply With Quote
Old July 28, 2011, 12:08   #90
IRONWORKER
Registered
 
FALaholic #: 48581
Join Date: Aug 2009
Location: Millspring NC
Posts: 2,855
Quote:
Originally posted by nwobhm


The stronger one costs $50 more. That's $50 more to double the life expectancy of the most expensive part on the gun. That aside... What if surplus becomes cheap again? Say .15 per round. Low ammo cost will equal more trigger time. If forged were $600 and cast were $225 cost would be important... but for $50.... Forged hands down.

+1 - This is the bottom line IMHO......... If the rifle is going to be a shooter that is going to see any real use the additional $50 it costs to have a forged rec instead of a cast one is a "no brainer" It's probably the best $50 you'll spend on a build......... If your building something to look at that will see only light use then by all means buy a "correct" cast rec - I have 2 of these from Enterprise (BGS & 1A1) & i plan on buying a Coonan STG rec, after i do i will NEVER buy another cast receiver.......... Contract receivers & older DSAs are THE ONLY choice for rifles that see hard-n-heavy use
__________________
M14 Armorer
IRONWORKER is offline   Reply With Quote
Old July 28, 2011, 12:36   #91
IRONWORKER
Registered
 
FALaholic #: 48581
Join Date: Aug 2009
Location: Millspring NC
Posts: 2,855
Quote:
Originally posted by Matt(formerly@)EntrepriseArms

Entreprise currently buys their casting from this company: http://www.fenicocastings.com/


ENTERPRISE CASTINGS SUCK i have never seen more pathetic, porous castings on a firearm than i have on the 2 shit receivers i bought from Enterprise, i had to send both back because of "welding" in several places & numerous (over a dozen on my BGS) pinholes - Check out the Brasshound group buy if you want to see current Enterprise quality
__________________
M14 Armorer
IRONWORKER is offline   Reply With Quote
Old July 29, 2011, 14:21   #92
jbrooks
Registered
 
FALaholic #: 10395
Join Date: Apr 2003
Posts: 1,731
I'm looking now at a report of tests conducrted on M-14 receivers and bolts in 1961, at the Watertown Arsenal Labs, Watertown, MA.

Recall, the M14 has/had a FORGED receiver and bolt. 8620H steel.

In response to a number of FAILURES of the FORGED M14 bolts, a series of studies was undertaken to see what specific kind and sequence of HEAT TREATMENT would provide acceptable performance of the forged components.

The title of the report now in my hands is "Mechanical and Metallurgical Properties of Carburized 8620H Steel for M14 Rifle Components", WAL-TR-739-13.

The report describes a series of Charpy impact tests and rotating beam (notch) tests in combination with various means of heat treatment. (air/oil quench, temperature, duration, etc.)

Why do I mention this?

Well, the fact that the early bolts were FOPRGED had NOTHING to do with outcome. They still failed by cracking at the locking lug.

It was the heat treatment that made the difference.

And the heat treatment remains the critical element to this day, regardless of whether the receiver/bolt is cast or forged.

Metallurgy has come a very long way over the past 50 years.

I am convinced that, as I mentioned above, that the QUALITY of the heat treatment is the deciding factor in the "great forged-vs-cast" debate.

And frankly, I'm skeptical of the 80,000 vs 40,000 round lifespan described in the SOF article being relevant today. And so far as I know, nobody with credible background and bona fides in metallurgy or material science has posted here yet.

If I'm wrong, I welcome your comments and resume.



JWB

Last edited by jbrooks; July 29, 2011 at 14:27.
jbrooks is offline   Reply With Quote
Old July 29, 2011, 16:28   #93
kev
Old Fart
Contributor
 
kev's Avatar
 
FALaholic #: 71
Join Date: Jul 2000
Location: Indiana and various others
Posts: 5,152
My only real concern is a cast T-1 receiver. That sounds like a stupid move to me,............intentionally sailing off into uncharted waters for the asthetics of a Type-1. I'm in love with the IDEA of a forged T-3, but a forged T-1 or T-2 or even a quality cast T-3 is okie-dokie fine with me. I draw the line at removing metal from a T-3 casting to produce an unproven T-1. I cannot fathom a reason for doing that.

I'm perfectly happy with any receiver that has an expected life of $20,000 to $40,000 worth of ammunition. Who wouldn't be? I'm not sure a cast T-1 receiver lives in this neighborhood.

I still predict failures in the future. It'll take the same type of firing that showed the weaknesses of the cast M1A receivers which may never be seen with today's ammo prices, but the potential is still there. BTW, semi-auto or full-auto isn't a factor. The rifle receiver has no idea whether there exists ten seconds or 1/10 seconds between firing impulses.
__________________
Gun control is not about guns; it's about control.

RUE?
kev is offline   Reply With Quote
Old July 29, 2011, 17:11   #94
jbrooks
Registered
 
FALaholic #: 10395
Join Date: Apr 2003
Posts: 1,731
Quote:
Originally posted by kev
..It'll take the same type of firing that showed the weaknesses of the cast M1A receivers...
What weaknesses in the Springfield Armory Inc M1As are you referring to?

JWB
jbrooks is offline   Reply With Quote
Old July 29, 2011, 18:41   #95
IRONWORKER
Registered
 
FALaholic #: 48581
Join Date: Aug 2009
Location: Millspring NC
Posts: 2,855
Cast M1A receivers are VERY strong, perhaps even stronger than a GI receiver BUT they are much thicker in several areas (especially the heel) - The same cannot be said of a cast T1 FAL receiver as no additional material was added, dimensionally they are identical to a forged T1
__________________
M14 Armorer
IRONWORKER is offline   Reply With Quote
Old July 29, 2011, 21:52   #96
jbrooks
Registered
 
FALaholic #: 10395
Join Date: Apr 2003
Posts: 1,731
Quote:
Originally posted by IRONWORKER
Cast M1A receivers ... are much thicker in several areas (especially the heel) ...
Certainly, SAI receivers are (were) identical dimensionally to USGI... I can't comment on any other supplier...

From Different's on-line RHAD,

"Every M1A receiver was given a final inspection at Valley Ordnance as part of the quality control program. The finished M1A receiver was placed on a magnetic base and compared using a Starrett dial indicator to a Winchester M14 receiver or custom made gage blocks surface ground and hardened to the USGI receiver blueprint dimensions. The Winchester receiver used for quality control purposes was cut off just behind the rear sight pocket. A less-than-80 % finished TRW receiver was used to check dimensional quality of the receiver heel rear end machining cuts. Every M1A receiver had a bolt inserted into it by hand to check for proper function before leaving Valley Ordnance. Springfield Armory, Inc. also performed inspection of finished M1A receivers. Any receiver deemed to have any machining errors, even minor cosmetic flaws, was sent back to Valley Ordnance for destruction. These less-than-perfect receivers, as many as 100 at a time, were destroyed by sledge hammer at Valley Ordnance then shipped back to Gray-Syracuse, Inc. for recycling back into raw castings. At Valley Ordnance, there were no “factory seconds” M1A receivers. M1A receivers are of good quality. Springfield Armory, Inc. has never used Chinese M14 parts in the assembly of its M1A rifles.

The Starrett dial indicator and custom gage blocks were transferred to Springfield
Armory, Inc. in 1996 along with the machine tools from Hillside Manufacturing and Valley Ordnance. Comparison of select fire M1A serial number 030061 to close up photographs of several USGI Winchester M14 receivers reveals nearly identical machining cuts on all surfaces."

My pre-ban SAI matches the USGI drawings with the obvious exception of the dismount notch and the slightly wider op rod "flat".

JWB
jbrooks is offline   Reply With Quote
Old July 29, 2011, 22:12   #97
Tim Dreas
Registered
 
FALaholic #: 17255
Join Date: Apr 2005
Location: York,PA
Posts: 891
Most of the internal radii in the M1A receivers are larger or "fuller" than the military M-14's. This may not be so much for additional strength as for getting a good, solid "fill" in the casting molds. They do have more material in them. I don't know for sure about the M1A receivers but some semi auto M-14 receivers have the rear heal a 10th of an inch thicker towards the front on the inside to mimic the shock spreading of the bolt and op rod to that of the semi auto Garand. The select fire M-14's cycled too fast in full auto with the Garand type set up. To slow the rate of fire a 10th of an inch was removed from the rear of the op rod should where it impacts the front of the receiver. This allowed the bolt to impact the receiver first while the op rod was still in rearward travel. This rebounding of the bolt while the op rod was still moving rearward slowed the rate of fire enough to allow the magazine to feed. In the Garand action in "theory" the op rod and bolt are suppose to contact the receiver at the same time. This divides the stress on the receiver between the front and rear, or at least it is suppose to work that way, it doesn't always. Sometimes the rear of the receiver has cracked due to the bolt impact. One of the designers of at least one of the semi auto receivers added the 10th of an inch back to the inside of the rear of the receiver to restore the stress-splitting of the Garand action and reduce the stress on the rear of the receiver.
__________________
http://www.mpri.com/
Tim Dreas is offline   Reply With Quote
Old July 29, 2011, 22:15   #98
Tim Dreas
Registered
 
FALaholic #: 17255
Join Date: Apr 2005
Location: York,PA
Posts: 891
This doesn't really apply to US-made FAL receivers, but FN did "upgrade" the type of steel used when the change was made from forged to investment cast receivers in Belgium.
__________________
http://www.mpri.com/
Tim Dreas is offline   Reply With Quote
Old July 30, 2011, 10:21   #99
Sampson1986
Renegade
Contributor
 
FALaholic #: 43374
Join Date: Mar 2009
Location: Montana, USA
Posts: 1,123
Quote:
Originally posted by LaConservationist
Just as Kev's data shows below.....
Forged Type 3,.........120,000rds? (a guess?)
Forged Type 2,.........100,000rds? (a guess?)
Forged Type 1,...........80,000rds (per FN)
Cast Type 3,..............40,000rds (per FN)
Cast Type 1,..............20,000rds? (a guess?)
Coonan Cast Type 2,..............100,000rds? (a guess?)

...

All this discussion of forged being better than cast is bullshit IMO. This is 2011 - not 1961. Technology (including manufacturing) has come a long way in 50 years. Short of running several modern day forged Type 1, 2, and 3 receivers against several modern day cast Type 1, 2, and 3 receivers and showing that the cast receivers consistently fail sooner, there is no clear evidence that forged receivers are better than cast receivers of similar quality.

Just the opinion of a civil engineering technology grad.
__________________
RENEGADE: an individual who rejects lawful or conventional behavior.
Sampson1986 is offline   Reply With Quote
Old July 30, 2011, 13:28   #100
IRONWORKER
Registered
 
FALaholic #: 48581
Join Date: Aug 2009
Location: Millspring NC
Posts: 2,855
Quote:
Originally posted by jbrooks

Certainly, SAI receivers are (were) identical dimensionally to USGI... I can't comment on any other supplier...


JWB


The main area where Springfield M1A receivers are much thicker is the receiver heel
__________________
M14 Armorer
IRONWORKER is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -5. The time now is 02:56.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
©1998-2018 The FAL Files