L1A1 / Inch SLR aka Brit FAL - mod's for functionality

[Artful]

Got a rifle that wasn't functioning properly - it was an inch Self Loading Rifle that was acting as a single shot.
The Coonan receiver had some extra material that needed to be removed and reset the head space.
The bolt would move a little but not enough to eject - the gas port was measured with a drill and was within
normal spec's - after trying several other possible thing for trouble shooting I had opened the gas port
from 0.095 to 0.102 and today it ejected with the escapement closed but only ejected about 6 feet.

But goes to show how just a little more gas does make a large difference - the plan is to enlarge
to 0.1045 to be able to use the gas adjustment. I would like it function with cast when I'm done.

[roverboy]

Hope you get done easily. Let us know how it does when your finished.

[edp2k]

Sounds like a receiver problem.

If the gun was built off of an inch FAL kit (i.e. was formerly a complete Brit/Can/Aus factory FAL before the receiver was chopped
and the gun turned into a kit)
then the gas port already was the correct size.

[Artful]

Gas port as delivered was 0.095 per my drill bit set.

[oneofsix]

Just curious, did you adjust the gas setting before opening up the gas port?


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[roysha]

Was that extra metal the little pad on the inside of the left side of the receiver which the carrier goes against?

[Artful]

Just curious, did you adjust the gas setting before opening up the gas port?


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Yes, was using the standard start out all open then turn down until locks back on magazine drill
First go around didn't eject - openned up and it started functioning but only with all gas going into the works
Now to test with just a little more gas so hopefully I'll be in the range to be able to adjust for weak to hot loads.
Interestingly I found the white box Federal M80 type ammo to be down loaded compared to Winchester and Surplus I tried (150-200 fps slower)

[Artful]

Was that extra metal the little pad on the inside of the left side of the receiver which the carrier goes against?

Yep, and the ejector block was a little high and the cut up by the barrel to make the curve was off a little. - Not a drop in project - Oh, and it's not numbers matching kit either.
It came with that stupid thumbhole stock so had to get a new lower frame with new pistol grip/stock to put everything into.

[oneofsix]

Yep, and the ejector block was a little high and the cut up by the barrel to make the curve was off a little. - Not a drop in project - Oh, and it's not numbers matching kit either.
It came with that stupid thumbhole stock so had to get a new lower frame with new pistol grip/stock to put everything into.

Ah, sounds like one the angry beavers had been chewing on, explains a lot of the issues you're seeing. Hope you're able to work them out.
I have a metric one that the magwell is a bit smaller than spec.

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[roysha]

Well, if you removed the carrier standoff, which is a NO-NO according to Coonan and several other folks that seem to know such things, how big of a locking shoulder did you have to use to get your headspace correct?

I have never had to open up the port on an FAL barrel and I would hesitate to open the barrel port any more than you already have.

Did you check to make sure your index holes in the gas tube were at 10 and 2 or 8 and 4 o'clock? If so was the tube nice and tight?

Did someone at some point unscrew the gas tube without removing the pin? That will cause a huge gas leak and pretty much ruin the threads on the gas tube. Trust me on that. Another lesson learned the hard way by me!

Having built a few of these over the years, I would first look at the gas tube where it screws into the gas block. It is amazing, at least to me, how small of a gas leak there will cause the rifle to malfunction. In a couple of situations I ended up soldering the gas tube in place to stop the leak. That was the case with the only L1A1 I ever built. The threads were just bad enough that no matter how tight I twisted the gas tube into the gas block it still leaked enough to cause problems. I even cut off the gas tube and rethreaded it but the gas block was a contributing factor also. I would dare say that 75-80% of the functioning problems that I have had with FAL, have been due to the leak at that point.

And by the way, I love my FALs. IMO they are so far ahead of the AR platform it isn't even close.

[Artful]

Well, if you removed the carrier standoff, which is a NO-NO according to Coonan and several other folks that seem to know such things, how big of a locking shoulder did you have to use to get your headspace correct?

I have never had to open up the port on an FAL barrel and I would hesitate to open the barrel port any more than you already have.

Did you check to make sure your index holes in the gas tube were at 10 and 2 or 8 and 4 o'clock? If so was the tube nice and tight?

Did someone at some point unscrew the gas tube without removing the pin? That will cause a huge gas leak and pretty much ruin the threads on the gas tube. Trust me on that. Another lesson learned the hard way by me!

Having built a few of these over the years, I would first look at the gas tube where it screws into the gas block. It is amazing, at least to me, how small of a gas leak there will cause the rifle to malfunction. In a couple of situations I ended up soldering the gas tube in place to stop the leak. That was the case with the only L1A1 I ever built. The threads were just bad enough that no matter how tight I twisted the gas tube into the gas block it still leaked enough to cause problems. I even cut off the gas tube and rethreaded it but the gas block was a contributing factor also. I would dare say that 75-80% of the functioning problems that I have had with FAL, have been due to the leak at that point.

And by the way, I love my FALs. IMO they are so far ahead of the AR platform it isn't even close.

gas tube is installed correctly - changed out gas plug for NOS - 0.262 locking shoulder to headspace correctly

And look inside your Fal's see any standoff in them? Mine don't have it.

[Artful]

with gas port openned to 0.104 the rifle now functions normally with all ammo tested - Yeah

Going to set the sights and see about loading some loads that jacketed and plated to see what kind of grouping I get.

Hoping winter comes soon as it sucks when it's 105 by 11 am here in the low desert.