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My FAL rifle will not cycle (Sticky from old site)

Posted: Thu Jul 13, 2017 1:18 pm
by Kevinofborg
Rapidrob on 4/23/2008:

Common FAL gas system problems and tips that may help.

With the importation of FAL / L1A1 Rifle kits into the USA, your parts kit / Century
Built rifles may experience these problems due to worn / wrong parts.

Among the most common symptoms of FTF/FTE (failure to feed, failure to extract) are the following:

1. The Bolt rides over the cartridge either causing a jam or crushes the cartridge case.

2. A new cartridge only partially chambers, the spent casing extracts and may or may not eject.

3. The new cartridge jams against back of receiver.

4. There is no apparent movement of bolt carrier regardless of gas setting.

5. Partial extraction of a fired casing regardless of gas setting, casing a jam or “ short stroke “.

6. Gas tube is blown out of gas block assembly.

7. I’ve tried all of the tips to increase gas pressure but the FAL still won't cycle properly.

8. Bolt closes easily on headspace gage but will not chamber round. The bolt locks up with excessive force.

FIRST, have you checked and made sure that your extractor hasn't broken?

Here is a list of tips that may help:

Before you do anything, ensure that the rifle is assembled correctly and there are no broken / missing/ metric in inch pattern parts that are not compatible.

1. The bolt is riding over the cartridge – This is a FTF problem and can almost always be traced to three common problems.

a. First, check to see if the magazine is being held in the magazine well tightly. If it is loose, your problem is most likely a magazine catch that is too short. The solution is to replace it with one with an extended magazine catch. Tapco offers extended magazine catches for about $15. Alternately you could weld a small bead on the end of the catch assembly. You will need to fit the modified parts to the rifle for proper operation.

b. Second, take the bolt and carrier out. With the dust cover removed, close the rifle’s action. Insert a magazine with two or more cartridges into the mag well. Now look at the magazine from the top of the receiver to see if the magazine looks like it is symmetrically positioned in the well, especially towards the front of the magazine. Most often a worn / sloppy magazine will cause this problem which will manifest itself as a FTF from one side of the magazine or the other ( left side, right side ). Also, check the magazine for a weak follower spring. When in doubt, replace the magazine with another magazine and try it’s operation.( dummy rounds work well for this tip )
c. Third, look for long deep scratches in the brass body of cartridges that have jammed. This is usually caused by sharp edges on the feed plate at the top of the magazine well and more often on cartridges that were feed from the left side rather than the right side of the magazine. Polish the edges of the feed plate with a 400 grit wet or dry sand paper. Crocus Cloth may be used also.

2. A new cartridge only partially chambers, the spent casing extracts and may or may not eject

a. If the spent casing eject reliably, check to see if the bolt carrier moves easily in the rails. The Imbel GL (gear logo) receivers are well made but a common problem is that the receiver rail is directly beneath some of the lettering stampings and occasionally gets distorted from an over zealous machine operator. The “Gunplumber” suggests taking a small Father unknown file and gently but firmly filing the raised rail surface smooth.

b. If you have an aftermarket HTS (hammer, trigger, sear) combo installed, remove and replace them with the pieces that were provided with the kit for troubleshooting. Century is not known for tight adherence to tolerances and their HTS will often cause FTF problems because they drag on the bottom of the bolt or carrier. Look for worn bright marks on the rubbing / binding parts.

c. Make sure that the recoil tube is straight and undamaged and that the spring and recoil plunger are lightly greased. A small amount of grease will not cause the rifle to lock up. The spring tube is inside of the butt stock. The spring is always under tension and needs to be removed carefully. A butt- stock spring tool can be had for under twenty dollars and will make this task very easy to do.

d. Check for weak recoil spring. Replace / repair as necessary.

e. Perform gas checks in Number 4. c, d, e, f, and i.

3. New cartridge jamming against back of receiver

a. This is most common with Century receivers. I have bad news, there is a problem with the design of the feed ramps that cannot be fixed easily. Polish the feed ramps with rouge on a Dremel Tool felt tip wheel. This may help the problem. Others have suggested MIG welding or brazing a small ramp and Dremeling it to shape. Proceed at your own discretion.

b. This can also be a problem caused by a slightly out of spec barrel. The barrel around the chamber cut should have a bevel about 1/8" wide. You can widen it slightly with a small file and polish it with fine sandpaper and then a felt tip and rouge on a dremel.

4. No apparent movement of bolt or carrier regardless of gas setting

a. Check that the gas plug is in the “A” position.

b. Did you remember to replace the gas piston and spring?

c. Check to make sure the gas tube is pinned in place and has not rotated. Ideally, the exhaust ports in the gas tube should be at 8 o’clock and 4 o’clock but if they are at 10 and 2, gas pressure may be lost down and around the gas tube’s threads. Your rifle may function, but a higher gas pressure will be needed. Excessive carbon fouling will be deposited onto the hand guards and barrel.

d. Ensure that the gas port is not obstructed. A bent paper-clip may be used to ream the gas port hole.

e. Check that gas piston is not undersized or worn. Proper diameter is between 0.429” and 0.431”. This is a common problem. Check your piston.

f. Excess leakage around gas tube, see No. 6. Teflon Tape wound carefully onto the threads will help prevent gas leaks.

g. Check that the bolt carrier “rat tail” is straight and in the recoil plunger detent and not jammed against the back of the lower receiver when closed.

h. Take the gas piston spring out and roll the piston on a flat surface to check for straightness. Reinstall the gas piston with the bolt and carrier removed. The piston should fall freely through the gas cylinder and gas nut. If not check gas tube and gas nut for roundness and damage. The barrel timing may also be “off-time “. This is called over/under clocked. Looking down the barrel at a distant object will reveal if the barrel is canted off center. Another easy test is to remove the gas piston spring and bolt carrier assembly from the rifle. Aim the muzzle towards the ceiling. Does the piston fall freely through the front hole of the receiver? Do you hear a thud as the piston centers itself through the front hole in the receiver? The piston must move freely through the hole and not bind or jam as it moves. If you have this problem take your rifle to a gunsmith for retiming of the barrel to the receiver.

i. Check for cracked / eroded gas block. The gas plug should not flop around in the gas block when locked into place.

j. Make sure you haven't put a metric gas plug in an inch gas block. A metric gas plug is about 3/16" longer than the inch plug. The gas plugs are not interchangeable.

5. Partial extraction of spent casing regardless of gas setting, the fired casing chamber jams or short cycles the bolt carrier.

a. This is most often a problem of not enough gas. What is REALLY is happening is that the spent casing is going back a small distance and then being pushed back forward into the chamber and shares solutions with No. 4. c, d, e, and f above.

b. Check that the gas piston moves freely. See 4. h above.

c. Check that carrier moves freely. See 2. a, b, and c above.

6. Gas tube blows out of gas block. This is a common problem in the G1 kits and the solution is both simple and cheap.

a. First, clean the thread of the gas block and gas cylinder and spread a small amount of solder flux on the threads.

b. Install and pin the gas tube with the exhaust ports at 4 and 8 o’clock on the rifle as if you are preparing to shoot it without the gas piston or spring installed.

c. Using Mapp gas, or other source, heat the threaded area and apply silver solder (preferably high temp silver solder because it is stronger) until it flows into the joint.

d. After the area cools, clean the excess flux off the area (some flux is acid based) and you may have to file the high spots off the solder joint with a small file.
Be careful not to prevent the gas plug from seating normally.

e. With a Dremel Tool cut off wheel, cut the gas tube off about 2 inches from the back of the tube (the end closest to the receiver) and discard it. Use sandpaper to smooth the end off. You are modifying the gas tube to the later “ short tube” configuration. You will not be able to remove the gas tube anymore, but you will have a gas leak proof gas block/tube assembly that will work.
Another option is to replace the gas block and gas tube with new parts. As these parts are getting harder to find in new condition, you may need to do the silver solder tip.

7. I’ve tried all of the tips to allow more gas to operate the piston but my FAL still won't cycle properly

a. Another tip is to allow more gas from the rifles bore. Remove the gas plug, piston, spring and tube. Place a 1/4" wooden dowel down the barrel under the gas port hole.

b. Starting with a #41( or so ) drill bit, insert the drill bit by hand through the bleed hole in the gas block and use it to determine the size of the gas port hole in your barrel.

c. Once you have determined the approximate diameter of your gas port hole, take the next larger drill bit and use it to ream this hole. Keep the drill speed slow and use plenty of cutting fluid and you will be less likely to break your drill bit off in the hole or cause a burr on the inside of the barrel effecting the rifles accuracy.

d. Test the function of the rifle once you have enlarged the gas port hole each size. You should see some improvement for each larger hole size. You may increase the size of the hole up to about 0.125" Do not open the hole so large that you allow excessive gas pressure into the system. While your rifle may function “ better”, you will hammer the piston and bolt to such an extent you may damage you receiver or parts. You will notice much harder felt recoil. A very small size increase will allow many more cubic centimeters of high-pressure gas into your rifles system. Once you have found the proper size hole to permit normal cycling of the gas system, test the rifle using the gas plug settings. (You should be able to stop the bolt carrier from moving at all;too very harsh operation by varying the plug settings.) You may have to do this drill tip if you have a cut-down 18” or shorter barrel or the gas port hole is too small from the factory.

8. Bolt closes easily on headspace gauge but will not chamber a round.

a. Does a cartridge fit into the chamber when you feed it by hand?

If not, Clean chamber thoroughly. Ensure cartridge is in spec. Lastly, you may need to ream the chamber slightly.

The loaded cartridge will chamber. It may be the top rear edge of the bolt binding up against the inside of the carrier. Place a piece of Playdoh, Duc-Seal or some other putty on the inside rear portion of the bolt carrier and then mate the bolt to the carrier as normal. Place the assembly into the receiver and try to push it closed with a cartridge on the face of the bolt until it binds. Pull the bolt and carrier out and observe the Playdoh. Is the putty being squeezed off of the bolt and into the bolt carrier? If so, file a small amount off the top rear of the bolt until it clears. Check again and continue to remove very small amounts of metal until the assemble will lock into the headspace block with the round riding the bolt into the chamber. (a dummy round is safer to use )
I hope these tips were of some help, these tips are a compilation of ideas from several members and web sites, enjoy your FAL rifle.

Tonkin Gulf Yacht Club

Re: My FAL rifle will not cycle (Sticky from old site)

Posted: Thu Jul 13, 2017 1:33 pm
by Kevinofborg
Some Replies.
jmcdude on 8/5/2008:
I experienced the item # 7 problem you describe, about ten years ago, and after a lot of it
ain't this and it ain't that, I determined that the barrel blow hole was just a few thou off of
perfect alignment, did just as you told and it functions just fine now. At the time, it WOULD
cycle with 180 gr soft point, expensive fodder for the range. Upon fixing it, it worky just
fine with 147 - 150 gr. but, it prints about 6 inch groups, not a very good barrel, but it works. My rifle is a 1995 era Century Canadian made receiver. Rest a box of parts.

Good info Bro.

jmcdude Psalm 1
rhughes on 2/14/2010:

Resurrecting an old thread.
I just finished a FAL that suffers from Problem #8. However, it will not chamber a round even without the carrier installed. the bolt will close on a GO gauge just fine, but on a cartridge it won't even come close to going into battery. Same problem occurs with or without the extractor and firing pin installed.
I think the cartridge is somehow binding on the recessed bolt face, but I can't tell exactly where or how.

Any ideas?

Rapidrob on 2/15/2010:

Can you chamber the round by hand? Does the cartridge seat all the way in to the extractor groove?
How far will the cartridge go into the chamber when is stops?
can you place a round in the chamber with no mag,and let the bolt fly home and chamber the round?
If not remove the locking shoulder and try the same thing. ( remove the firing pin or make a dummy round )
If the bolt goes all the way forward, your head spacing ( locking shoulder ) is way too tight. File down or buy a thinner shoulder.

rhughes on 2/15/2010:

Thanks for the reply...
Lost of stuff here.... Let's see.
Will the cartridge seat in the extractor groove? Yes, if I remove the bolt and snap it in by hand

How far will the cartridge go into the chamber? I haven't put a depth micrometer on it, but a Mark I Eyeball comparison between a round and a GO gauge indicates "all the way". Miking this is my next step. The barrel is chrome lined

Can I chamber a round by dropping one in the chamber and letting the bolt fly home? No.

Removing the locking shoulder and retry? Haven't done this (yet) but it is on the list. I'm really leery of setting headspace using a cartridge as the gauge, especially in this case.

One thing to note. If I pull the extractor and firing pin and attempt to chamber a round by hand with just the bolt installed, it still binds up. With this set up, you can actually look through the extractor groove and see the base of the cartridge. It is obviously NOT seated against the bolt face but is possibly binding on the rim of the bolt. I haven't tried to polish this area yet, but I may give it a go.

Thanks for the feedback and suggestions!

Rapidrob on 2/15/2010:
Is the bolt and carrier matched? Same inch/metric?

rhughes on 2/15/2010:
They are both metric. At first I thought is was a carrier/bolt problem but found that the bold will bind up even without the carrier installed. The cartridge base is a very close fit to the bolt face. Normally I would think this is a very good thing but It may be that the tolerance is just too close and can't account for the minor differences in cartridge spec vs. h/s gauge.

Rapidrob on 2/15/2010:
OK. Now we get into the fun stuff. Please provide close up,clear,photos of the receiver,bolt,carrier and how the barrel is timed to the front of the receiver and good photo's of the breech area. FAL's bolt together very easily and your problem is not normal. I for one do not use a HS gauge when I build these rifles. I use a pin gauge in place of the locking shoulder, find the true tight head space,then back off by .002.
Is the ejector in the way?
rhughes on 2/15/2010:
This is the second FAL I've built; had no trouble with the first. I built this one on an Entreprise Arms Type 3 and had absolutely no trouble aside from this. I've only used dummy cartridges to headspace pistol caliber carbines. I guess it would work as well with a FAL; just never tried it. I use a pin gauge rather than the locking shoulder, find the max headspace with a NO-GO then work down to the minimum. In the case of this particular rifle, the absolute minimum locking shoulder size was .261; the GO gauge locked at .265 I dropped back to .263 locking shoulder.

Originally I thought the ejector might be the problem so I popped out. The binding still occurs. Also it doesn't interfere with chambering a GO gauge; not the proper way to headspace, but the best way I could figure to start diagnosing the problem.

The forums posts really help in thinking this through. The more thought I give to it, the more I wonder if the problem might be a slightly over-sized receiver rail. I didn't notice a problem (of course I wan't exactly looking for that) but it could be a burr or something forcing the bolt face UP just enough to be not quite in line with the bore. That would account for the apparent binding on the cartidge base.

I'll try to get some pics tonight with the "good" camera.

rhughes on 2/15/2010:
OK, I just got really impressed by Entreprise Arms. After I beat my head on this problem for a while on Saturday, I decided to do a web search for similar problem. I posted a short comment to EAI to see if they had any reports of similar problems. Wasn't sure if I would hear back.
I just got a call from them offering to take a look at the upper half and help diagnose it. If I can't figure it out pretty quick, I may ship it out to them this week. It will cost a bit to FedEx, but it's better than having a pristine wall-hanger

rhughes on 2/15/2010:
Pic #3
Bolt closed on the GO gauge.

I took another one with the NO-GO in place. It obviously would not lock up, but the picture quality was so bad it was a waste of bandwidth to upload it.

Rapidrob on 2/15/2010:
Hey! Photo #2, what is that at 1-2 o'clock? It looks to be some milling/casting leftovers?

rhughes on 2/15/2010:
Pic #4
Last one.
This one shows the bolt and carrier binding up with a cartridge in the chamber. The extractor and firing pin have been removed. You can see the space between the base of the cartridge and the bolt face. I don't have a feeler gauge thick enough to be sure, but I think the gap is between .070 and .090; very hard to tell.

I decided the GO gauge will chamber because the diameter is slightly smaller than that of a cartridge and it has a little room to shift in the chamber. A spec cartridge will not; there is absolutely no play.
rhughes on 2/15/2010:
I believe it's a combination of glare, lint (from a shop rag I was using), and a bit of grease. I thought the finish job on the receiver was pretty good. I didn't find much to clean up; just a bit at the edge of the pivot hole and t the rear of the receiver. The upper/lower half lock up is very tight.

rhughes on 3/7/2010:

Pulled the upper and lower back apart and took a careful look at the arrangement of the bolt, receiver, cartridge and chamber. It became apparent that the bolt was riding up on the feed ramp and binding on the bottom edge of the cartridge base. This would NOT occur with a headspace gauge due to the fact that the gauge is not really a tight fit in the chamber. (It measures length, not diameter.)
Some careful measurement showed the feed ramp, or more precisely the ledge just ahead of the ramp area, to be approximately .008 to high. I say approximately because it was very hard to measure with a caliper. I took several measurement and worked off an average.
I unbreached the barrel, carefully lowered the ledge and smoothed the ramp, re-polished both, and reassembled. Works like a champ!! :D :D
Feels great to be able to solve a problem !