Imbel FAL Jamming

[samwho]

I've got an Imbel FAL that jams after every shot. After firing, the spent cartridge seems to be extremely difficult to extract and the bolt will usually only move back about 1/2 inch even with the gas pressure adjustment at maximum. The rest of the cycle needs to be done manually with a LOT of difficulty. I've replaced the gas tube, which looked a bit worn. Also the recoil spring set. The bolt, carrier, extractor, etc. all seem to be fine. I have a Tapco gas piston on the way but I'm starting to wonder if the cheap Czech ammo I've been shooting may be the culprit. Can anyone give me an idea of what to try next to fix this?

 

[Mac's]

Here's a few general things to check:
1...Does the bolt cycle smoothly with no rounds chambered?
2...If you remove the spring from the gas piston, will it drop smoothly thru the hole?
3...Did the rifle ever function correctly?
4...Are you getting any gas pressure leakage around the gas adjuster?
5...Is the headspace correct?
6...Have you tried decent ammo?
7...Is it hard to extract the fired case all of the way to the end or just at the beginning?

Since you stated that it will only partially extract the fired case and that it is very difficult to extract the rest of the way by hand:
1...You can eliminate the gas system and piston entirely. It will only give a push to the bolt carrier and not obstruct hand cycling in any way.
2...Try a different better grade of ammo.
3...Look for a problem in the chamber that's holding the fired case. What do the fired extracted cases look like?
4...Look for a hack job on the locking shoulder to bolt lockup. That can cause a bad un-lock sequence.
5...Check for a mis-matched bolt and carrier. Under load, they can be binding against each other.
Hope this helps. Keep yer powder dry, Mac.
Tuff-Gun Finishes. The Name Says It All.
Mac's Shootin' Irons
http://www.shootiniron.com

 

[samwho]

1...Does the bolt cycle smoothly with no rounds chambered? Yes
2...If you remove the spring from the gas piston, will it drop smoothly thru the hole? Yes
3...Did the rifle ever function correctly? Yes
4...Are you getting any gas pressure leakage around the gas adjuster? Don't think so
5...Is the headspace correct? Yes
6...Have you tried decent ammo? Not yet
7...Is it hard to extract the fired case all of the way to the end or just at the beginning? Just in the first inch or so


Thanks for the tips Mac. That'll give me a better handle on what's going on. I thought at first that the chamber might be damaged but it specs out OK and the shells don't look chewed up but there is a bit of brass shavings in the works when I pull it all apart. I'll check the things you mentioned!

 

[JohnKSa]

That's a classic symptom of the gas setting being too low. The empty is not extracting.

Are you sure it's set to maximum and not to minimum?

If it is set to maximum then perhaps the gas port is clogged, something is misaligned, or there's too much gas blowing by the piston or leaking somewhere.

 

[Travis Bickle]

It could be the magazine. Try a different one.

 

[JohnKSa]

Ok, you've got me curious. How does the magazine affect extraction?

 

[samwho]

The gas setting is definitely set at maximum, the gas port is not plugged in any way and I've tried a number of different mags, including foreign made, US made and I've replaced all my floorplates with US made ones.

 

[Travis Bickle]

Ok, you've got me curious. How does the magazine affect extraction?

I have no idea, but I know it can because I own an FAL and it always jammed with one magazine I had.

 

[Mac's]

The gas system makes it "go" by giving a hard push to the bolt carrier. SamWho said:
"""extremely difficult to extract and the bolt will usually only move back about 1/2 inch even with the gas pressure adjustment at maximum. The rest of the cycle needs to be done manually with a LOT of difficulty"""

That indicates that the bolt carrier is getting the push from the gas piston but something is binding up. A weak gas system, whether it be from worn parts, a plugged gas port or incorrectly adjusted adjustment ring, would cause a partial extraction but would not cause "The rest of the cycle needs to be done manually with a LOT of difficulty". A faulty gas system would not cause a Lot of difficulty with a manual extraction.

Since different mags have been tried, that pretty much eliminates a mag problem. How does it chamber a fresh round? Easily?

There are only three areas that can cause the kind of problem that you're describing:
1...The bolt/carrier/locking shoulder lock up. Take that apart and look for any damage.
2...Some kind of issue with the chamber. Crud build up, physical damage, cr@ppy ammo. Try honing the chamber and/or using different ammo.
3...Some kind of issue with the trigger group. If the hammer is binding up after it slams into the firing pin, it will cause difficult extraction. As the carrier travels backward, it has to push the hammer back against the spring and reset the trigger. Some of the early USA made replacement parts had problems with pieces breaking off. Take that apart and look for damage.

My first guess at a long distance diagnosis will be #2. Chamber and/or ammo.

Keep yer powder dry, Mac.
Tuff-Gun Finishes. The Name Says It All.
Mac's Shootin' Irons
http://www.shootiniron.com

 

[Eric F]

Well the classic imbel fal jam problem, mine was a combination of, too tight a chamber, mis matched bolt and carrier, miss machined receiver, the internal rails were too tight, and lastly too tight a gas tube causing too much gas flow restriction. It was shipped back to imbel, they sent me a new gun, it was better, but I sold it in sheer and utter disapointment

 

[JohnKSa]

That indicates that the bolt carrier is getting the push from the gas piston but something is binding up. A weak gas system, whether it be from worn parts, a plugged gas port or incorrectly adjusted adjustment ring, would cause a partial extraction but would not cause "The rest of the cycle needs to be done manually with a LOT of difficulty". A faulty gas system would not cause a Lot of difficulty with a manual extraction.

Ok, here's what I'm thinking is happening.

The gas is pushing the bolt back far enough to pull the case almost clear of the chamber, but not far back enough to eject. Then the recoil spring is jamming the case back into the chamber where it sticks tightly.

What he's describing are exactly the symptoms I experienced with my Imbel FAL as I was adjusting the gas setting. Until I got it opened enough to function the action properly, after each shot the bolt would be forward or mostly forward with the case tightly stuck in the chamber. Once I got the adjustment open enough (setting 4) it worked perfectly.

 

[Eric F]

spring bind........there is a good idea too, was this a thumb hole stock that got converted?