Headspacing is THE most critical part of any firearm build. DO NOT get this part
wrong because it could cause the loss of an appendage or even worse, your life if done improperly.
Headspacing a FN/FAL is relatively simple though, just pay attention to details and you should have
no problems. Once you understand the concept it's a piece of cake. There's an
excellent post on The FAL Files Forums that decribes the process in easy to understand
terms. Even I had no problem understanding it. =)
First off, the barrel's chamber, the bolt/carrier assembly and all gages used in this process
need to be cleaned thoroughly. We're working in thousandths of an inch, so the cleaner
the better. Next, take out the bolt's extractor (Top Left Pic) to keep it from interfering
with headspace gage rims. The nifty little tool in the pic made this simple to do, however be
sure and control the extractor lest it gets shot into outerspace when removing it from the bolt.
You need gage pins (Top Right Pic) of various sizes to act as the locking shoulder (LS) which
controls headspace in a FN/FAL (Bottom Left Pic). You can get rods that are stepped in .001
increments or get individual gage pins that are one size for each increment. I went with the
latter and ordered mine from MSC Industrial Supply. I got them in .001 increments covering the .254" to
.269" range. MSC part numbers for these can be found in this
"FAL Files" post. I wanted my carbine to meet Nato 7.62 minimum headspace specs, since I plan
to shoot surplus ammo through it. I plopped down an extra few $$ for the Clymer Go/No-Go Gauges
(Bottom Pic) because they are within a 1/2 of a thousandth (.0005) from that spec. Note the green
and red rings on the gages that make it easy to tell at a glance which one is the GO (Green) or NO-GO (Red) gage.
Once ya have the extractor out of the bolt, the chamber and all gages/parts cleaned thoroughly, slide
in the "Go" headspace gage then pick a LS gage pin and slide it into the
hole (red arrows) in the upper receiver where the LS will reside. I picked the .261" gage pin as the
first to try in hopes that I would get lucky and be able to use the .262" LS that came with my kit.
Placing the bolt carrier (w/bolt installed) in it's rails of the upper receiver, I slid it forward
as if it was chambering a round to check and see if it would close with firm thumb pressure. It did not
close no matter how much I wanted it to, but I now knew which direction in LS gage to go with (smaller).
I went for the .004" smaller (.257") LS pin and the bolt carrier closed with very little thumb pressure.
I then took out the "GO" gage and placed the "NO-GO" gage in the chamber and
repeated the above process. The bolt carrier at first didn't close, but I exerted more thumb pressure
and it did close. It should NOT close at all on a "NO-GO" gage! I took
out the "NO-GO" gage, put the "GO" gage back in and
placed the .258" pin gage in. This time the bolt carrier closed with thumb pressure. Put in the
"NO-GO" gage and it refused to close no matter how much force I put on it.
Soo.. What I need for a correct NATO spec headspace is a .259" locking shoulder which allows for
.001" setback.
Since the LS I have on hand won't give me the headspace spec I wanted, I had to find another
one to replace it. Jen, the administrator of The FAL Files provides a "LS Exchange Program" for
FALaholics like myself. I contacted her, and luckily she had a .259" LS for trade. Jen will replace
your original LS with a Vanden Berg Custom locking shoulder for $12 (money order or certified funds)
which includes shipping/handling. For priority mail, add $4.50. Email Jen at
orders@fnfal.com to find out if she has the LS you need for your FN/FAL, then mail the funds along with
your LS to "The FAL Files - P.O. Box 58553 - Webster, TX 77598-8553". If you would rather keep your existing
LS, Jen will also sell you a LS outright for $25, add $4.50 for priority mail (if desired). After the correct
LS arrives, it will need to be pressed or hammered into the upper receiver slot, then Final Assembly can commence. Stay Tuned!!
Shoot Safe!!!
Email suggestions and comments to:
bandit@wecsog.org
Web Hosting by:
Bandit's Web DesignŽ - Best viewed at 1024X768 resolution
Headspacing is THE most critical part of any firearm build. DO NOT get this part wrong because it could cause the loss of an appendage or even worse, your life if done improperly. Headspacing a FN/FAL is relatively simple though, just pay attention to details and you should have no problems. Once you understand the concept it's a piece of cake. There's an excellent post on The FAL Files Forums that decribes the process in easy to understand terms. Even I had no problem understanding it. =)
