• WTB / WTS / WTT ADS
    All Advertisements, including Want to Buy, Want to Sell, Want to Trade, Belong in the MARKETPLACE ONLY. Any new threads posted offering an item for sale, looking to trade or buy an item which are posted outside of Marketplace will be deleted without notice or warning. Existing threads will be moved to marketplace.
  • Marketplace Feedback Ratings
    The Marketplace feedback ratings system is now back. You can now leave feedback for your Buy / Sell / Trade transactions. Instructions on how to leave feedback ratings can be found HERE

GTotW: HEADSPACING

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
As requested by Dougjones31, this is one installment of a HOW TO section for working and building FAL's. MODERATOR, please move this to the appropriate forum.

Please do not post comments or threads because this post is meant to be for reference only. If you see any mistake, please PM me and I will edit the content.

The standard safety warnings are in effect. Always verify weapons are unloaded and clear before starting work. Use eye and ear protection to prevent injury.

Disclaimer: this is the method that I use for headspacing the FAL's. I have combined techniques from various sources to come up with a procedure that I am comfortable using. This is not the only way you can go about headspacing your rifle. The tools shown are again what I use and am comfortable with. There are other styles and types for you to use, you will have to make your choice.

The first step in HEADSPACING the FAL is to make sure the weapon is UNLOADED:
 

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step 2 is to separate the upper and lower halves of your rifle. This just makes things easier to handle and move around.
 
Last edited:

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step 3 is to remove the Bolt Carrier (BC) with bolt, along with the dust cover. This is in preparation for extractor removal and to allow you to see what you are doing.
 

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step 4 is to remove the extractor from the bolt.

Notice how I am using the proper tool for the job. I learned that the WECSOG method does indeed draw blood. And I found it cheaper to buy the correct tool than to continuously keep restocking my first aid kit.

Clean the bolt with some brake parts cleaner, gun scrubber or other cleaning agent. Set the extractor aside and in a safe place that you can find later on. Don't ask me how I know to do that.
 
Last edited:

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step 5 is Clean the chamber. Use a chamber brush and patches until the chamber is spotless. Dirt and crud can cause improper headspace readings.
 

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step six is to Re-Install the Bolt Carrier and Bolt assembly back on to the receiver. Insert the GO HEADSPACE Gauge in the chamber. Gently cycle the B/C open and closed several times, checking for freedom of movement and rough spots. Correct these problems before continuing any further.
 
Last edited:

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step 7 is to insert a pin gauge and determine if it is the correct size. Slowly close the B/C assembly while holding the pin gauge in the Locking Shoulder hole. If the B/C closes with no pressure, open the B/C, remove the pin and replace with one that is larger. Continue to repeat these steps until the B/C assembly will not close, or resistance is felt. When resistance is felt, or the B/C will not close, go the next SMALLER sized pin gauge and close the B/C assembly. If it closes, then that is the size to use.

There has been considerable discussion about 2-thumbs pressure, 1-thumb pressure, etc. The whole key to the correct size is that you DO NOT USE EXTREME FORCE to close the B/C assembly on the headspace gauge. I use about the same pressure on the B/C assembly as that used on the ammo while loading a magazine. If it takes more force than that, I go to a smaller size pin gauge.

EXPLANATION: While some have verified the above step by using the NO-GO gauge, I do not. I feel that by taking the B/C to the point of not shutting or shutting with extreme pressure and then backing off .001" pin gauge size, inserting a NO-GO gauge that is .004" larger is redundant. Others have gone to a .004 smaller pin then used the NO-GO gauge, again to verify their initial size determination. I do not use this method either because I feel that by using two different sizes of pins, the wrong pin sizes could be used to determine LS size, causing the headspace to be wrong. I try to keep my procedures in line with the K.I.S.S. principle.
 
Last edited:

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step 8 is the hard part. Determine your Locking Shoulder (LS) size. Check the size of the pin gauge determined in step 7. In my case it was a 0.262- gauge. I am also using Forstner headspace gauges, which measure 1.630 for the GO and 1.634 for the NO-GO giving a difference of 0.004. To put my headspace in the middle of the range, I would have to loosen the determined headspace by 0.002. Some folks here believe in setback, which means that the parts will "settle in" after firing the rifle and the clearances will get bigger. I too believe in setback and want to take it into account. So I will make my headspace about 0.001 tighter to counteract the setback.

Are we all confused now? It is really quite simple.

Pin gauge = 0.262
mid range = -0.002 looser
setback = +0.001 tighter

LS size = 0.261 in the mid-range
 
Last edited:

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step 9 is getting the proper sized LS. I purchase mine in the correct size because this is a critical component and could have serious problems if a failure occurs. Plus, the angle of the mating surface has been the subject of many past discusions.

Once I have the LS in hand, I like to measure it to double check for the correct size.
 

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
I also like to make sure the dog bone section of the LS fits in the receiver cut out. Don't ask how I know this can be a PITA if you find out it doesn't fit while trying to install the LS.
 

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step 10 is to install the LS. Lubricate the long portion of the LS and insert it into the receiver LS hole. As you can see from the attached photo, I use my vise to press the LS into place. You can use C-clamps, hydraulic presses, and even vise-grips. Take notice that the pressing tool I use is nothing more than a 1/4" drive hex head bit held in place on the vise jaws by a cheapo magnet (saves needing 3 or 4 hands). The wood is used to prevent damage to the reciver from the jaws.

Some guys say it is alright to hammer the LS into place. I do not. The LS is a hardened piece of steel and if you hit the dog bone wrong, you could crack or break it off, ruining the LS.
 

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Step final is to insert the NO-GO gauge and see if the B/C assembly will close. It should not close at all. Remove the NO-GO and insert the GO gauge. Attempt to close the B/C assembly. It should close with light pressure.
 

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Now that you have adjusted your headspace, re-assemble your FAL and take it to the range.

WAIT Did you remember to re-install your extractor? It could be embarassing if you didn't do this step.

Hopefully, by reading and looking at the pictures, you guys can see how to headspace your FAL's. Some guys like tight chambers and some like loose chambers. Do your research and decide which way you want to go.


This photo is for the new guys to see what the heck I was working on, since some of the parts didn't look like normal FAL parts
 

grifter95

Well-known member
FALaholic #
20148
Joined
May 31, 2006
Posts
68
Location
Southeast Georgia
Feedback: 0 / 0 / 0
Great photo documentation. I did mine slightly different and would like your opinion. I took the locking shoulder that cam with my kit and installed it. It was too large. So I took it out and carefully stoned .001" off and reinstalled and checked it with the go-gauge. I continued this until it would close on the go-gauge with light pressure. I then removed it and took an additional .001" off and re-installed. BC closed with light pressure. Took the go-gauge out and replaced it with no-go-gauge and verified that it would not close. I then removed the LS and measured it with a caliper. I then ordered the corresponding size from DSA and presto. This method took alittle time but it saved me having to buy a set of gauge pins!
 

flintoid

Member
FALaholic #
62125
Joined
Dec 1, 2010
Posts
14
Location
MA
Feedback: 0 / 0 / 0
an excellent guide. This should be a sticky- I don't know how many times I had to look for MosinGuy's posts in order to find this gem.

Helped me headspace my first build! :fal:
 

gunplumber

Arrogant Bastard
Gold Contributor
FALaholic #
96
Joined
Jul 21, 2000
Posts
28,406
Location
Surprise, AZ
Feedback: 353 / 0 / 0
Excellent write-up. I disagree on the vise.

Hammering is just fine - safer in my opinion. I know exactly how much force is on the LS when I'm driving it with a punch (no you don't hammer directly on the LS 'cause you can break the dogleg off). Put it in a vise, and with the mechanical advantage there is not "oh wait, this is too tight something is wrong"

I drive the LS with a punch until just before it is to enter its recess. Then I take a special tool (ok, it's just a tiny crescent wrench) and make any final adjustments to the locking shoulder's orientation - because a hair out of alignment and that dogleg will crack when you hammer (or press) the LS the rest of the way in.

If I am going to use a mechanical means of insertion, then I use the arbor press. Still has better "feel" than screw press like a vise.

Brit armorer instructions show a press and says not to hammer.

Aussie armorer instructions specify a hammer.
 
Last edited:

tac-40

Moderator, Armed Curmudgeon
Staff member
FALaholic #
12090
Joined
Oct 14, 2003
Posts
10,523
Location
SC-Low Country
Feedback: 76 / 0 / 0
Excellent write-up. I disagree on the vise.
Mark, I agree and disagree with you on this one. I have hammered in LS and not had any problems. But then again I have been a mechanic for most of my life and have a feel for working with metal. And it is definitely faster for me to hammer one in.

However, when I did this thread, I was asked to consider what the average new FAL Files member had to work with in respect with tools. And to consider their level of mechanical ability. In teaching to the lowest common denominator, most work shops are not equipped with an arbor press but do have a vise. And the vise will work as a press if used correctly. Letting a noob start wailing away with a hammer on the LS dogleg is a sure fire way of breaking the thing. So to keep it simple and safe, I used and described this method.
 

gunplumber

Arrogant Bastard
Gold Contributor
FALaholic #
96
Joined
Jul 21, 2000
Posts
28,406
Location
Surprise, AZ
Feedback: 353 / 0 / 0
I understand what you are saying, but I come to the opposite conclusion - Particularly for those not used to working with tools, I think it is much harder to "sense" the amount of force when using a vise, which incorporates significant mechanical advantage, than it is with hammer.
 
Top