Grooving a Barrel

[juanmurmylo]

What tool is used for grooving a FAL barrel?

Is it a custom one? or is somewhere I could buy one?

[Ron Walker]

A special rifling lathe is necessary, whether you do cut rifling or button rifling. Very large, expensive, and hard to find. Ron

[bykerhd]

Are you talking about cutting rifling INSIDE a barrel.
Or, cutting grooves, called flutes, into the EXTERIOR of the barrel for weight reduction, better cooling and cool appearance ?

Cutting rifling is a very specialized job and probably best left to the few specialists left that do it.
The exterior work requires a lathe and an experienced machinist for the work.

[juanmurmylo]

I have at my disposal a big lathe and very capable people of making a barrel.
I refer to the inside.
We dont care to throw the first barrels.
We will learn till we make a shooter.

were could I get that drill?

or does anyone have a drawing to make one?

[easttex]

If you figure out how to use a lathe to cut rifling inside a barrel, please let me know. I've been wondering about that for years.

[W.E.G.]

http://riflebarrels.com/articles/barrel_making.htm

[juanmurmylo]

thats a really nice article. Very informative.

Once I read an article about all the tooling and drills to do that, but I lost it. I downloaded the pics but cant find them... maybe at work computer? damn

[6ppc]

Originally posted by juanmurmylo
thats a really nice article. Very informative.

Once I read an article about all the tooling and drills to do that, but I lost it. I downloaded the pics but cant find them... maybe at work computer? damn

Save your money and just buy what you need, you could buy a blank and have someone profile it to your needs. Barrel makers make barrels and tire makers make tires. Special equipment like a brake drum lathe.

[juanmurmylo]

Save your money and just buy what you need, you could buy a blank and have someone profile it to your needs. Barrel makers make barrels and tire makers make tires. Special equipment like a brake drum lathe.

It seems that you dont get the whole idea. If I wanted to ASSEMBLE a rifle I would buy kits, parts and file what doesn´t fit. I did that already.

I want to make, build, I´ll go as far as I can. I´m not addicted to shooting. Thats part of my normal life. I need something new. I do this because I learn new things while experimenting. Can´t you get that? If I cared so much about saving money I wouldn´t even go to the range. 100 rounds in a couple of minutes don´t you believe we´re not saving money that way? And by the way, Im not rich, Im an average Joe that instead of spending his money in beer, dope or hookers is intending to learn.

By the way I have a specialized machinist who owns lathes, EDMs etc and hi loves guns just like I do and is teaching me and I teach him what I know. Its fun and it´s worth trying. And if I do not succed, well at least I tryed and made my best effort. I´ll never regret that. But I will regret If I never try.

[1gewehr]

Good for you! The more people that know how to do things, the more likely it is that somebody can still make a barrel in years to come!

[bykerhd]

Actually, there are quite a few reference works around about how the barrel makers in the late blackpowder era use to rifle their barrels.
You wouldn't want to use their barrel MANUFACTURING techniques for high pressure smokeless loads, but the rifling techniques could be used. Maybe.
Versions of the equipment could also be made that should work. Again, maybe.

There have been low volume, home operation barrel makers up until fairly recent times. You may be able to find some information about their techniques.
The Internet may, or may not be of much use. It might help you locate some information sources.
Good luck.

[ggiilliiee]

work with a "gundrill" and a tube tir fixture ...drawbar set up high feed rate, slow rotation .like a sunnin hone.....make one.... grind cutters set up the stroke and rotation ....nothin to it ..hehe .
the real trick is to get one end online with the other end ....a mystery the smurfs here havent gotten yet ..ie 5" inch groups ...and get that edm out of yer haid ..heheh .

[juanmurmylo]

Wait I believe, and this is just my opinion. Is that most people in USA is getting used to hi tech.

Here, in the 3rd world. I´ve seen very fine competitions barrels made by people with knowledge instead of Hi tech. Using large common lathes and the apropiate tools.

I have had made ejector blocks, ejectors, and many other small and more detailed pieces by expert machinists that worked as New Old Stock. Never a complaint.

Many of you are seing this with $$$ eyes. I try to make $$$ with things I master. But this is just my hobby and challenge.

I´ll post these days a 3D model of the barrel. (thanks GP)


And yes giilliiee, the key here is to keep the the tube concentric and online one end and the other.

By the way, I´ve seen some machinist keep a very complex piece 0,001MM not 0,001 inch, 0,001 mm all the way with very rudimentary tools. So its a matter of mastering, patience and some love for your work.

I dont know how much time is this going to take. But for sure my friends and I are interested in having some made. At least just for pure fun at the range.

FM manufactures rifles using SAE 6150 cold martensite (martelado en frio).
Chrome, chamber or full chrome inside.

What I do not know is the characteristics of the rifling. I know its 6 turning to the right (I dont know the exact connotation in english sorry) and one turn in 12in.
I lack the depth of the riffling and their width.

[kotengu]

Do you have cerrosafe down there? It should be relatively easy to pour a casting of a few bores and measure the lands and grooves. I know there are many different styles (ie: 2 groove, 4 groove, etc.), and I would imagine many different specs to each style to argue about.

As long as you're going to all this trouble - forget about lands and grooves all together and set up to make polygonal rifling!

I say good for you - it's always more fun, educational, and rewarding to see if you can build it yourself with skill instead of throw money and technology at it. I am constantly amazed at the level of skill and ingenuity used both in the USA's past (ie: WWII creations/production) as well as less technologically advanced country's present.

There's a guy in Pakistan that posts on a jeep forum from time to time - he makes all his stuff with a torch and an anvil in a dirt-floored shop. The real kicker is he even "makes" his own acetylene for the torch!

[W.E.G.]

Now, on the matter of "grooving," that's more of an art form...

[Dwalton]

Here's another article i found .
Shows some machinery and tooling . Explains cut , button and hammer forged .
http://www.firearmsid.com/Feature%20...anufacture.htm

Also brownells sells a book of a guy that built his own barrel making machine .


Enjoy


DJW

[Dwalton]

Here it is . Boy i didn't have Brownelle's bookmarked
think i fixed the link ?
http://www.brownells.com/aspx/ns/sto...le=BILL%20WEBB

DJW

[W.E.G.]

Originally posted by Dwalton
Here it is . Boy i didn't have Brownelle's bookmarked

http://www.brownells.com/aspx/ns/sto...le=BILL%20WEBB'S%20RIFLE%20BARREL%20MAKING%20MACHINE

DJW

linky no worky

[juanmurmylo]

make polygonal rifling!

Glock barrels use polygonal rifling (as many others I know...). And sure my glock hits exactly where I want.

Has anyone seen or tried polygonal on a 7,62 barrel? That, If never made, would be interesting and revolutionary.

Pros/Cons?

jaja ....grooving together with a pict

No, we dont have cerrosafe over here. Unlucky for me, this country is being ripped off its weapons. so everyday, less people has guns, and therefore, gunsmiths and gunshops are starting to scarce. Thats why crazy ones like me want to master these arts.

Here's another article i found .

Very cool, It´s worth the time reading it. Thanks!

[6ppc]

Originally posted by juan murmylo


Glock barrels use polygonal rifling (as many others I know...). And sure my glock hits exactly where I want.

Has anyone seen or tried polygonal on a 7,62 barrel? That, If never made, would be interesting and revolutionary.

Polygonal rifling in rifle barrels have been used for a long time now. The M24 and M40 sniper rifles have this rifling. I have a Remington 700 5R milspec that has this and a 40X with same. These guns shoot .6 or better MOA with the Sierra 168 MK bullets. Once polygonal rifled barrels are broken in you will never see any copper fouling and there said to produce less chamber pressure then conventional rifling. There the pros I don't know of any cons. Getting back to your barrel project, Why don't you concentrate on just getting a bar of steel 24" long and putting a .299-.300 hole through it with a 16RMS finish or better. After you succeeded in doing this then you can worry about rifling it.



Pros/Cons?

jaja ....grooving together with a pict

No, we don't have cerrosafe over here. Unlucky for me, this country is being ripped off its weapons. so everyday, less people has guns, and therefore, gunsmiths and gun shops are starting to scarce. That's why crazy ones like me want to master these arts.






Very cool, It´s worth the time reading it. Thanks!

[juanmurmylo]

Yes, I get your point. One at the time. But sometimes while I wait I start planning for the next. jeje. Right now I waiting for my first manufactured at the cave firing pin. I have to pick it up tomorrow at my friends machine shop.

Then for next week the Gas piston (it got delayed)

Then the receiver (have to wait the cnc series to clear)

Then The Picattyny mount (I have already the Schem,the STEP and 2 blocks of 6064 T6)

And while we wait for all this, I´m working on the barrel and will start working on the carrier and bolt

Its realy easy to get the cilinder of steel here. I live in an industrial town. I can buy aluminium and steel just like candys. Thats not the issue. I worry more about knowing what to do in order to supervise others work and obviously learn how to do it myself.

Regarding the cerrosafe. What kind of alloy is it? tin/lead


Does anyone have information like this for a 7,62 rifling or polygonal rifling?

[juanmurmylo]

Mmmm. I love internet....
My choices are....

Broach Rifling
OR
Electrochemical Rifling

In a process that eliminates the conventional machining of metal, rifling is formed by wet-etching the interior of a barrel under an electric current. The metal inside the barrel is actually eaten away or dissolved to create grooves in the barrel. An electrode (cathode) that has metal strips in the shape of the rifling is placed in the barrel (anode) and the the assembly is submerged in a salt solution. An electric current is applied and the electrode is moved down the length of the barrel and twisted to create the spiral shaped grooves. As the current travels from the barrel to the electrode metal is removed by electrolysis thus forming the grooves in the barrel. This process creates the rifling in the barrel very quickly and does not require consumable tooling.


Why? I have 4 EDM machines at my disposal. I could make a polygonal shape electrode and make the rifling. Does anyone agree/disagree?

[easttex]

Juan,

If my memory serves me, polygonal barrels are made in a rotary hammer forge. And, that's what H&K uses on their rifles. That may be difficult to do without the proper equipment.


As an aside, is it really possible to EDM a hole 7.823mm in diameter that's 53.34cm+ long?

[juanmurmylo]

At the shop they have both, EDM and Electro Erosion machines. I have seen them work and yes, they can erode small diameters, very small, depending on the electrode you make.

The problem is what you point. Its 53cm long. Thats a problem to solve but I dont think its imposible. Tomorrow when I pic up the Firing Pin I´ll ask the experts what they have to say... by the way, they are the ones that proposed me to make the barrels im just gathering information jeje.

[DrDuc]

I watched a friend make a connecting rod bearing with a micrometer. a bench grinder and his eyes. When he finished it was 0.0001 out of round. Certainly close enough for Velocette specs.
He could file a square hole in a piece of stock and pass a bar through it with 0.001 clearance on each side.
He worked for Tyrrell F-1 team and later Newman -Haas Racing.
He's now into 50BMG long range work after an Army stint as an EOD.

[1gewehr]

Originally posted by juanmurmylo

Glock barrels use polygonal rifling (as many others I know...). And sure my glock hits exactly where I want.

Has anyone seen or tried polygonal on a 7,62 barrel? That, If never made, would be interesting and revolutionary.

Pros/Cons?

HK has used polygon rifling on it's rifles for many years (mid 70's IIRC). Most commonly found on G3, HK91, HK93, MP5, etc. The downside is some steel-core bullets don't stabilize well. Those with thick jackets do better as the softer metal conforms to the bore more easily.

[AndyC]

Originally posted by juanmurmylo
What I do not know is the characteristics of the rifling. I know its 6 turning to the right (I dont know the exact connotation in english sorry) and one turn in 12in.

6 land, right-hand twist - and a 1-in-12 (abbrev = 1-12") rate-of-twist.

[djanes]

Juan:

I think you can make a barrel rifling machine ! I did a simple search using Google and a few things came up.

For your material and process, you should follow:

1) Source the correct steel or stainless material. Consider looking at the Following web pages to understand the materials being used. Douglas, Green Mountain, Lilja, and such. I have found the Lilja site to be filled with pictures and data with respect to materials. Also .50 BMG information. Make that your next project.

Some Links:
http://www.riflebarrels.com/articles...fle_barrel.htm

2) Your next effort will be to make deep holes ! This is done with a machine called a Gun Drill. It uses a long single lip drill. The machines are made by companies like Diamond and others. Do a Google search for Gun Drill. Again some good information and pictures can be seen at the Lilja site - see link below.

http://www.riflebarrels.com/articles...le_barrels.htm

Once the deep hole is done, ream to correct size and then button rifle the grooves in. Button rifling is not the only way to do this. Pacific Tool and Gague in Washington state has buttons. search for PTG or chamber reamer. You will need chamber reamers also, but done later.

As far as the rifling machine or process, you can make your own machine. See the link below.

http://www.practicalmachinist.com/vb....html?t=126815

3) Once you have some deep holes in the barrel blank, the barrel should be contoured. That is, turn the outside between centers. I am sure that the exact step by step process may also involve stress relieving. Most of the countouring I have seen is done on a lathe, between centers. You may need to use a steady rest and CNC would be best due to some of the long tapers.

4) One of the last few things will be to chamber and press on the gas block.

~ on the intresting side, you may want to build a fixture to orient the thread on the barrel in relation to the location that the gas block needs to be located. As you know, the barrel when threaded into the receiver bottoms out on the outside not the inside (end of the barrel). You want to orient the gas block in relation to the thread in it's last position next to the shoulder.

If you build a gage that threads on the barrel, with a slip ring on the outside. The slip ring would have a set screw and a pointer. Thread it on one barrel and align the pointer with the gas block. Lock the set screw. You should find that the next barrel you try will have the gas block in close to the same position.


Just a few thoughts - I will design the thread gage described above and post it.

Keep working hard

Dustin

[juanmurmylo]

Thanks for the info djanes!!! pretty usefull

I have the posibility of buying Steel hollow Cilinders. I choose the inner and outter diameter . What do you think about this? I believe the material is extruded to whatever you want. There are some standar inner holes that can be made bigger in a simpler way than depending on a gundrill.

[[486]]

Originally posted by juanmurmylo

I have the posibility of buying Steel hollow Cilinders. I choose the inner and outter diameter . What do you think about this? I believe the material is extruded to whatever you want. There are some standar inner holes that can be made bigger in a simpler way than depending on a gundrill.

That would certainly make it easier to bore it out the rest of the way, just use like a piloted reamer, so it follows the inside hole that is already drilled, probably plenty straight too...

[djanes]

Juan:


You do not want to use anything with a hole in it to start...... That is not safe.... All the material that has a hole in it to start is a welded seam or welded seam with a DOM (drawn over mandrill) process. The seam is the problem.

You need to start with solid !!!

Think in terms of 4140 or 416 stainless

The diameter you should start with is 1.25" (31.75mm - metric equal) or slightly smaller.

Cut the material into a rough length that is 6mm longer than the finished length. Some would say that you want it much longer to permit clean-up on the threaded end and the muzzle end. This is OK also.

Face both ends to make ready for Gun Drilling

Gun Drill to a size just under finish, ready for reaming

Ream to size

Rifle the grooves using a pull through (Button) or cut process

Finish hone

..... All this comes from just looking around. If you have any questions I am happy to help and would enjoy contributing to your project. I can send models of items I have done in DXF or IGES. Or native ProE format.

Regards

D

[juanmurmylo]

The seam is the problem.

Yes, but these cilinders are seamless!!!

Well, I have many opinions here. Guess this is going to be proof and error until it gets done.

This weekend Ill start working on the cad of the barrel.

djanes, do you have the dxf of the rifling?

[Sgt Rock]

Juan This is not meant as a joke. Unfortunately the photographer didn't include pics of the rifeling machine. It was similar without the large wheel drive. A cutter was pulled through the barrel by a wooden donut that turned on a spiral wooden shaft. This process was repeated many times and the cutters got larger until the barrel was done.

[juanmurmylo]

yes!!!! thats what Im talking about!

cool!

[Sgt Rock]

The machines are in colonial williamburg VA. I took a welding class in 1990 and the instructor showed a video of a gunsmith in Colonial Williamsburg that was making flint locks the old fashioned way. Completely by hand. 3 wire twist hammer welded and then the wire was wrapped around a mandrel and hammer welded into a tube. Then drilled. then rifled. I don't recall whether he lapped it but then he proof tested the barrel using if I remember correctly 4 times the normal charge of powder. The hammer and frizzen and such were made by sand cast etc, etc. At that time his rifles started at $10,000.00 and he had a waiting list.

[6ppc]

Originally posted by djanes
Juan:

I think you can make a barrel rifling machine ! I did a simple search using Google and a few things came up.

For your material and process, you should follow:

1) Source the correct steel or stainless material. Consider looking at the Following web pages to understand the materials being used. Douglas, Green Mountain, Lilja, and such. I have found the Lilja site to be filled with pictures and data with respect to materials. Also .50 BMG information. Make that your next project.

Some Links:
http://www.riflebarrels.com/articles...fle_barrel.htm

2) Your next effort will be to make deep holes ! This is done with a machine called a Gun Drill. It uses a long single lip drill. The machines are made by companies like Diamond and others. Do a Google search for Gun Drill. Again some good information and pictures can be seen at the Lilja site - see link below.

http://www.riflebarrels.com/articles...le_barrels.htm

Once the deep hole is done, ream to correct size and then button rifle the grooves in. Button rifling is not the only way to do this. Pacific Tool and Gague in Washington state has buttons. search for PTG or chamber reamer. You will need chamber reamers also, but done later.

As far as the rifling machine or process, you can make your own machine. See the link below.

http://www.practicalmachinist.com/vb....html?t=126815

3) Once you have some deep holes in the barrel blank, the barrel should be contoured. That is, turn the outside between centers. I am sure that the exact step by step process may also involve stress relieving. Most of the countouring I have seen is done on a lathe, between centers. You may need to use a steady rest and CNC would be best due to some of the long tapers.

4) One of the last few things will be to chamber and press on the gas block.

~ on the intresting side, you may want to build a fixture to orient the thread on the barrel in relation to the location that the gas block needs to be located. As you know, the barrel when threaded into the receiver bottoms out on the outside not the inside (end of the barrel). You want to orient the gas block in relation to the thread in it's last position next to the shoulder.

If you build a gage that threads on the barrel, with a slip ring on the outside. The slip ring would have a set screw and a pointer. Thread it on one barrel and align the pointer with the gas block. Lock the set screw. You should find that the next barrel you try will have the gas block in close to the same posi


It would be easier to cut the tenon thread , then align in a fixture for positioning the gas block. Remember this guy says he already built a receiver and where is the thread lead positioned at the face of action? That would have to be timed as well.




Just a few thoughts - I will design the thread gage described above and post it.

Keep working hard

Dustin

[juanmurmylo]

Remember this guy says he already built a receiver

I haven´t built a receiver yet.

And I have the schematics showing the timing of the threads, for the barrel and for the receiver. So that shouldn´t be a problem.

[jbgw]

Sgt Rock that picture is too cool
The last rifling set up I saw there was a wooden cylinder wrapped with a spiral of iron strip. Drawing the rod in and out made the rifling. This seems to be an improvement on that device.
I see what Juan is trying to do.
Everyone here thinks he is building a rifle
They are wrong.
He is creating his own personal database from which he can branch out and use the knowledge to create new solutions.
Using the information you have to apply it to solutions in new situations is the true implication of intelligence.

[juanmurmylo]

Made out using virtual gundrill and P4 CNC

[juanmurmylo]

Barrel: 16.25In
8 land, right-hand twist - and a 1-in-12 Polygonal Rifling
Its so possible in the computer. Now the challenge is to make it possible on metal.

[G_FAL]

It most definately needs to be seamless steel tubing.

Some years back Barrett received some barrels that someone up the
supply line had substitued/supplied seamed tubing instead of seamless.
While proof firing the 50BMG , things became very exciting!!!!

[jbgw]

Please dont forget the gas port and the extractor cut.
Chambering can come later.

[kotengu]

Why 8 lands? I know Glock uses octagonal rifling on their 45, but I think they use hexagonal (somebody correct me here) on everything smaller. Something about the fit of the smaller bullet in too many sides of the polygon.

I do know the 45 Glocks are extremely accurate, so maybe octagonal is the way to go. I was just curious as to why you chose it -

[juanmurmylo]

Just MY theory using what I´ve heard and read until now.

More lands provide more accuracy but less proyectile speed.
Being a 16.25 barrel it will have less accuracy, so with 8 lands I try to compensate that.

Just correct me If Im wrong, im not a barrel expert.

[kotengu]

Makes sense - more sides to the polygon would mean it is closer to a circle, and should mean a better fit for a round bullet (better accuracy). Of course, the close you get to a circle the more friction you will have, so that would mean less velocity.

Interesting - I'd never really thought about it that way before. Good luck!

[djanes]

Juan:

Enclosed is a concept gas block orientation fixture. If you calibrate the fixture with a known-good barrel assembly first, it all works.

Use the 2 parts to the Left (in the picture) Thread the part with the shoulder on to a barrel with a gas block. The sleeve with a slot and two holes slips over the part with the shoulder. It also has 2 locations for set screws.

Place the barrel in the fixture and place the cap over the top ( the one with the slot).

Now, orient the first part so that the slot lines up with the slot in the cap. Use the "Key" to check the orientation.

At the other end of the big block, the gas block is held vertically and has a hole to drill the gas block retaining pin ( used for new assembly).

Once the fixture has been calibrated, a new barrel can be inserted and have the threads lined up for the gas block insertion and pinning.

I will post the same type of tool for the receiver.

You need to make tools to make parts....

Dustin.

[djanes]

Just checked - I can't post attachments


Cut and paste the link...

D

[juanmurmylo]

Click Here To See Djanes tool

[juanmurmylo]

Here they are,
Extractor Cut and chamber... does anyone know the exact location of the gas port?

[BlasterLP]

Very interesting project you have here!

Something to take into consideration when figuring the number of grooves and lands to be produced in a barrel is what effect will this have on chamber pressures? ?

Check this link out regarding work that has been done with the 6.8SPC chamber specs and also results from different groove and twist rates.

http://www.ar15performance.com/6_8_facts___load_data

I hope this helps you somehow with your 7.62 FAL barrel project.

good luck
LP