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Blood of Tyrants
April 29, 2004, 16:15
Due to the many, many threads dealing with failure to feed and failure to extract problems, I decided to put up this FAQ dealing with that subject.

First, ensure that the extractor is not broken or worn badly. Also, make sure your gas piston is not bent and the barrel is timed properly. (Search two AND rods AND method )

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

1. Bolt riding over the cartridge either causing a jam or missing the cartridge altogether

2. New cartridge only partially chambers, spent casing extracts and may or may not eject

3. New cartridge jamming against back of receiver

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

5. Partial extraction of spent casing regardless of gas setting, casing jams hard in chamber

6. Gas tube blows out of gas block

7. I've done all the stuff to get more gas but my FAL STILL won't cycle properly.

8. Bolt closes easily on headspace guage but will not chamber round. Jams up tight.

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

I will deal with them in order.

Before you do anything, ensure that the rifle is assembled correctly and there are no broken parts.

1. Bolt 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 mag well tightly. If it is loose, your problem is most likely a mag catch that is too short. The solution is to replace it with one with an extended mag catch. Tapco offers extended mag catches for about $10 (note: Tapco no longer sells these, others may but I don't know). Alternately you could weld a small bead onto the end, probably no more than 1/16" to 1/8" will be plenty. In either case you will have to “file to fit” for a good tight hold.

b. Second, take the bolt and carrier out and remove the dust cover and close the rifle. Insert a mag with at least two cartridges into the mag well. Now look at the mag from the top of the receiver to see if the mag looks like it is symmetrically positioned in the well, especially near the front. Most often it is well used mags that have this problem which will manifest itself as a FTF from one side of the mag or the other. Also, check the mag for a weak spring. In either case. Get a new mag and throw this one away. (Yes, you can replace a weak spring if you have another bad mag laying around but at $10 each for new mags, it is hardly worth it.)

c. Third, look for long fairly deep scratches in the cases of cartridges that have jammed. This is usually caused by sharp edges on the feed plate at the top of the mag well and more often on cartridges that feed from the left than the right. Polish the edges of the feed plate with 400 grit wet or dry or finer.

2. New cartridge only partially chambers, spent casing extracts and may or may not eject

a. If the spent casing ejects reliably, check to see if the bolt carrier moves easily in the rails. 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 overzealous machine operator. Gunplumber suggests taking a small bastard file and gently but firmly filing the “hump” off.

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.

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.

d. Check for weak recoil spring. R&R 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 a felt tip and rouge on a Dremel and it may fix it. 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. You DID remember to put the gas piston back in, didn’t you?

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, it will not affect operation.

d. Ensure that the gas port is not obstructed.

e. Check that gas piston is not undersized or worn. Proper diameter is between 0.429” and 0.431”.

f. Excess leakage around gas tube, see No. 6

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.

i. Check for cracked gas block.

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. This hardly seems likely because your piston would protrude and prevent the carrier from going all the way forward.

5. Partial extraction of spent casing regardless of gas setting, casing jams hard in chamber

a. This is most often a problem of not enough gas. What is REALLY 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, 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 file the high spots off the solder with a small file if your solder job isn’t too pretty or interferes with the gas regulator.

e. With a Dremel 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.

7. I've done all the stuff to get more gas but my FAL STILL won't cycle properly

a. Okay, one more trick to get more bleed gas. Remove the gas plug, piston, spring and tube, and the front sight, spring, and index plate for a metric rifle. Put a 1/4" wooden dowel down the barrel.

Note: Metric barrel gas ports are drilled perpendicular to the barrel and you gain access to the gas port by removing the front sight. Inch barrel gas ports are drilled at an angle through the regulator hole on the gas block, just under the gas regulator.

b. Starting with a #41 or so drill bit insert it 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 the hole out. 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.

d. Test the function of the rifle once you have gone up a couple of sizes. You should see some improvement. You can increase the size of the hole up to about 0.125" until you get enough gas for proper operation.


8. Bolt closes easily on headspace gauge but will not chamber round. Jams up tight.

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

No. Clean chamber thoroughly. Ensure cartridge is in spec. Lastly, you may need to ream the chamber slightly.

Yes. It could be the top rear edge of the bolt binding up against the top inside of the carrier. Put a piece of Playdoh or some other putty on the inside top rear of the bolt carrier and then put the bolt in the carrier. Put them both in the receiver and try to push it closed with a cartridge in the bolt until it binds. Pull the bolt and carrier out and observe the Playdoh. Is it pinched all the way to the carrier? If so, file a small amount off the top rear of the bolt until it clears.

Blood of Tyrants
April 29, 2004, 16:15
If I have said anything that is incorrect or omitted anything, please let me know and I will edit it.

critterflht
April 29, 2004, 18:08
Originally posted by Blood of Tyrants
If I have said anything that is incorrect or omitted anything, please let me know and I will edit it.


Nice job, thanks.:bow: I'd like to add that the gas system checks under #4 also apply to the failure to eject part of problem #2-
Lee:fal:

flejl
April 29, 2004, 20:25
Great information!

Thanks

g5
April 30, 2004, 12:06
Nice post. Thanks!

Blood of Tyrants
April 30, 2004, 12:59
Suggestions noted and incorporated. Also, highlighting done for easy reference.

Blood of Tyrants
May 20, 2004, 12:46
Bump it back up.

Blood of Tyrants
March 05, 2005, 17:23
A bump for the newbies.

mikess512004
March 05, 2005, 22:45
Excellent job. Might want to add emphasis on making sure the gas piston drops completely thru the gas block and the gas tube, stopping only at the receiver end gas plug. Some of the TAPCO gas tubes won't allow the gas tube to do this, whcih causes frustration.

lyndo
March 14, 2005, 17:05
I had non-working (FTF) group of mags. After lotsa head scratching and comparing w/ the working one, it looked like the box had been dropped or stacked under a few cases of ammo for the trip to the gun show. the Hole in the top was narrower. W/ wide pliers I tweeted the lips upward a little, then (unloaded ) i shoved the mags into the reciver ( causing any over tweekulation to be done away w/) Causing the mag lips to fit tightly against the reciver. Now all of them work.

Blood of Tyrants
December 28, 2005, 18:55
Newbie bump.

Jon Frum
December 29, 2005, 18:53
Do not forget to lube and:

MikeyB
December 31, 2005, 14:21
I have been having FTF problems with my unibrow Century receiver. The tips of the bullets was jamming between the feed ramp and the barrel face at the 5 and 7 o'clock positions. I polished the feed ramps and the barrel face without any luck. I found by bending the lips of the magazine (the ones towards the front) down helps with the feeding. This causes the rounds to feed towards the center of the feed ramp where it has a easier path to glide up into the breech.

MikeyB

Blood of Tyrants
January 01, 2006, 18:40
Originally posted by MikeyB
I have been having FTF problems with my unibrow Century receiver. The tips of the bullets was jamming between the feed ramp and the barrel face at the 5 and 7 o'clock positions. I polished the feed ramps and the barrel face without any luck. I found by bending the lips of the magazine (the ones towards the front) down helps with the feeding. This causes the rounds to feed towards the center of the feed ramp where it has a easier path to glide up into the breech.

MikeyB

I have wondered if putting a tiny bit of the epoxy used to seal automotive gas tanks in above the "unibrow" to build a smooth ramp would fix it. The stuff is easy to work with and could be easily rmoved if it screwed things up. The one concern would be not to make the ramp so big as to interfere with the bolt.

MikeyB
January 01, 2006, 18:58
I was thinking the same but using JB Weld.

MikeyB

drakejake
January 01, 2006, 19:30
For what seems to be a photo of material put into the gap between the feed ramp and the barrel lip, look at post by thompsonjoedeals on p. 2 of this thread:

http://www.falfiles.com/forums/showthread.php?s=&threadid=158154&perpage=30&pagenumber=2

I think that this might be a valid fix if done properly.

Drakejake

Blood of Tyrants
January 01, 2006, 21:47
Originally posted by MikeyB
I was thinking the same but using JB Weld.

MikeyB

I think JB Weld would be too "runny" at first and might go into places you don't want it to. The gas tank sealer would be putty-like initially allowing you to shape it with your fingers or a small spoon shaped object. After it is molded, gently put the bold and carrier and let the bolt make whatever impression it might and then remove it and allow the putty to harden.

drakejake
January 03, 2006, 18:06
Further thoughts on the bullet tip jamming against the feedramp or between the feedramp and the barrel lip:

It seems that if the problem is in the specs of the receiver, the cause of the jamming is probably:

1. That the feed ramp is too close to the mag well or front of the mag, or

2. The feedramp is sloped upward at too great an angle.

Either of these situations would cause the tip of the round to get hung up before the round can escape from the mag feedlips and move up to the chamber. If the ramp is too close, there isn't enough room for the round to move forward while still held down by the feed lips. If the angle of the ramp is too steep, the round is also unable to move forward and escape the mag.

On my FAL, rounds generally fed OK from the left side of the mag but hung up when fed from the right side. This might imply that the specs of the two sides of the ramp are different and this looks to be the case. It may also be that there are different factors involved in feeding from the two sides of the mag, perhaps because of the shape of the follower.

If the round is able to clear the feed ramp, but gets stuck in the crevice above it, hung up on the sharp edge of the bottom lip of the breach or chamber, the problem could be that the ramp is too low to allow the round to clear the sharp edge of the barrel or that there really shouldn't be such a crevice there in the first place. Sometimes the rounds in my FAL would get hung up on the edge of the barrel. To try to prevent this, I rounded off this edge manually with a small stone from a Dremel kit. This may have helped somewhat.

To counteract the the negative effect of the out-of-spec Century receiver, I have tried to bend the mag feed lips upward to allow the top rounds (left side and right side) to sit up as high as possible and thus escape the feed lips sooner. This is a matter of degree because if you bend the lips up too far the mag cannot lock into the mag well and rounds will not be retained in the mag. If you raise the front of the lips too high, the bottom of the case may be depressed, causing the bolt to ride over it instead of stripping it from the mag. While fiddling with mags at home I check to see if the top rounds sit up high, can be easily pushed out of the mag by hand, and if a good bit of the case bottom is exposed to the bolt while sitting in the mag. I also have done lots of hand-cycling with the firing pin removed and/or the safety on. Hand-cycling seems to be a a fair predictor (not 100%) of whether the mag will feed rounds properly at the range. This work seems to be successful because I have now a number of mags which feed properly. I also polished the bottom edge of the rails and the feedramp, but I do not know whether this helped overcome the jamming.

Drakejake

MGoBlue
April 10, 2006, 20:51
My gas plug does not have an "A" at all, but it does have a long line / indent from front to back on one half. Would that be the same as the "A" side? I just finished shooting yesterday and had the "bolt carrier would not cycle problem" and I suspect I put the gas plug in wrong, after reading some posts.

Great informative thread!

Blood of Tyrants
April 25, 2006, 20:35
remove and look at the shiny part of gas plug. When in "repeat" mode, the slot in will be down to allow the gas to get to your piston. When in "grenade" mode, the slot will be up and the gas port will be covered.

Vic303
May 22, 2006, 22:54
Thanks for solving the #4-5 problem Dave was having with his FAL. Looks like the rat-tail was not in the detent.

Blood of Tyrants
May 09, 2007, 19:24
bump for newbies

ftierson
March 28, 2008, 12:31
Originally posted by Blood of Tyrants
bump for newbies

Yup, and again...

^

Forrest

GM4spd
November 25, 2008, 21:31
Originally posted by Blood of Tyrants
If I have said anything that is incorrect or omitted anything, please let me know and I will edit it.

Great info---I had to go all the way to step#7---opening the gas port
with your directions----what I didn't know was that my Brit INCH
barrel has the port @ 45 degrees! I was looking for something straight
in @ 90 but figured it out ok and went slow---I opened all the way to
.125 haven't range tested yet but has got to be better then closed down
to 1 or 2 on the gas to get any functioning. Thanks Pete

GM4spd
December 14, 2008, 09:20
Originally posted by GM4spd


Great info---I had to go all the way to step#7---opening the gas port
with your directions----what I didn't know was that my Brit INCH
barrel has the port @ 45 degrees! I was looking for something straight
in @ 90 but figured it out ok and went slow---I opened all the way to
.125 haven't range tested yet but has got to be better then closed down
to 1 or 2 on the gas to get any functioning. Thanks Pete

UPDATE!!!! after a range trip,I went thru almost 200 rds on a #6--setting
never one failure of any kind, Thanks for the great info. Pete

glenbjackson19
October 06, 2010, 11:40
just wanted to say that i was having problems extracting and read this but it didn't help because it didnt say anything about a OUT OF SPEC CHAMBER!!!(SHAME ON CENTURY)
I figured it was CHAMBER by turning off gas system(turning the "G" up on the gas plug) this cancels out the possibiltiy that it could be jamming on the way back(recoil spring, carrier, timing, gas system itself). Then try to manually cycle it, it should cycle w/o much force. BUT i had to slam on the ground to extract so that only leaves one thing that the shell itself is some how stuck in the chamber. Well in my case turns out that the chamber had a slight bulge in it and so the case would expand into it and act as a "locking lug" basically!! Try to hone it could fix it but i just bought another barrel!
hope i helped someone

Blood of Tyrants
November 13, 2010, 23:28
You can take a bump out of a chamber with a chamber reamer. Rental is only about $30, a lot cheaper than a new barrel.

glenbjackson19
November 13, 2010, 23:36
im actually going to try that wont hurt it since i already got a new one. but i dont think it's a bump im pretty sure it's a ballooned chamber and reaming it out to make it "flush" and extract smoothly i think would give the casing too much room to flow and may rupture??? ill let you guys know if i ever get it done.
And THANKS(Blood of Tyrants) for the troubleshooting guide!

STG-98
May 03, 2011, 00:01
8. Bolt closes easily on headspace gauge but will not chamber round. Jams up tight.

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

Yes. It could be the top rear edge of the bolt binding up against the top inside of the carrier. Put a piece of Playdoh or some other putty on the inside top rear of the bolt carrier and then put the bolt in the carrier. Put them both in the receiver and try to push it closed with a cartridge in the bolt until it binds. Pull the bolt and carrier out and observe the Playdoh. Is it pinched all the way to the carrier? If so, file a small amount off the top rear of the bolt until it clears.

I got one of these Jams. Rifle functioned well on several types of ammo, but locked up tight on 2nd round of the last brand. It is headspaced pretty tight.

Bolt appears to be locked in battery. When I tried to decock, the carrier rode back only a bit further, firing pin is out of its aperture in the back of the carrier.

Any advice on getting this round out, and preventing this? Other than not using Turkish 7.62 in this rifle again ?

Ok, scratch that. It was a failure to extract, not a live round. Got it out by a little extra force on the bolt and carrier. Will take her back out today probably and see how she runs.

klashy47
August 18, 2012, 22:27
Great info! Thanks for making this stuff readily available!!

meltblown
October 13, 2012, 09:53
I've had a broken firing pin that protruded into the bolt that would not allow the round to feed when dropping the bolt release. Cycled fine when running.

matrixalgorithm
April 08, 2013, 12:30
Hi guys,

I am new to this forum and would appreciate some help. I recently bought a DS Arms Fn-Fal (all stock, 21in barrel, fixed stock, iron sights). Took it to the range the first time and I started getting feeding issues. The round does not feed from the magazine into the chamber. It also seems like there isn't enough space for the round to eject from the magazine and enter the chamber. So I called Ds Arms and explained the problem. They sent me two new mags and I am still seeing the same issue. When I put a round in the chamber using the charging handle, the round doesn't fully enter the chamber and the bolt doesn't completely close. I can usually clear the jam manually by extracting the magazine and then the bolt usually closes. Then it lets me get off a few rounds before the same issue happens again.
Needless to say, I'm a bit frustrated. I spent a lot of money in getting this rifle and I would really appreciate it if somebody could help me out.

Thank you.

Peckerwood
July 12, 2013, 00:31
Thanks

MakNorinco
December 28, 2013, 19:18
whoops....

Humm
January 27, 2014, 04:18
New guy here. I'm a new owner ( almost a year) of a STG58 on a Hesse receiver that had all the problems, feed ramp too steep, goes bang only once, fail to cycle. I smoothed the ramps so that it would feed a while back. I found this page by googleing and followed the trouble shooting above. I had a gas tube that is soldered and out of position, the gas port was only half open. I drilled it out rather than sweat it and try to turn the tube. Added a pin made of a drill bit. I opened up the port under the sight to 7/64 and what do you know--it goes bang more than once. Happy . I thank you for the tips. I sold a nice in the box Springfield Golden age with the intentions of this STG being my 7.62--way cooler. I have a few bugs to work out yet, the mag rocks so that it won't pick up the next round unless I hold it forward while shooting. It does the same with new and used mags, the new ones fit tight. It don't lock back on last shot (appears to have an inch latch control) , don't know if that is it or not. I'll weld a little bead on the mag and see if it helps the mag stay in. Getting long winded--I just want to say Thank You!