PDA

View Full Version : ammo no completely cycling weapon


merrden
June 17, 2007, 21:58
I have a L1A1 rebuild. My trial ammo is Malaysian MG and Indian OFV ammo. The gas system is fully closed. Sometimes the weapon extracts and ejects but fails to bring another cartridge to battery. Early on it would not extract or eject at all. I finally took the gas tube out finding it to be barely screwed into the front sight base.After screwing the tube as far in as the vent slot allowed and reattatching it at the rear the weapon began to function. However most pictures seem to depict the rear nut as being flush to the receiver. Mine has a 1/8 inch step between the nut and receiver. It is bottomed out so to speak flush against the receiver.
OK guys does anyone have any ideas as to the source of my problem? I had heard that the OFV ammos was not liked by FALs at all. I have found the Malaysian ammo to be inconsistant in accuracy in my M1A and MK 2 enfield, so it is suspect as well.
I have some primo Radway green, LC M80, Port.,FN, and So. African, but 3 - 4K at best total. Unless we are blessed with some one releasing quite a few mil. rounds of mil spec surplus, it is time to invest in a Dillon set up and start operating our shoots like camp perry. Most lower grade mil spec is loaded to group 6 inches at 100 yds.LC. Radway, and some others are loaded to print 4 inches at 100 yds.. Please advise.

Merrden

shootist87122
June 17, 2007, 22:43
There should be a cross pin (under the gas tube) located under the gas adjustment nut to keep the gas tube from backing out. Could be the gas port is also plugged up and needs cleaning.

Mosin Guy
June 17, 2007, 22:57
http://www.falfiles.com/forums/showthread.php?s=&postid=1915851#post1915851 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.

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. Alternately you could weld a small bead on the end. 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 eject 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 over zealous 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.

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 amout 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. put a 1/4" wooden dowel down the barrel.

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" untill you get enough gas for proper operation.


8. Bolt closes easily on headspace guage 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 cartride 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.

merrden
June 23, 2007, 15:47
Hi Guys: We found that our gas tube was loose . Evidently the breakdown was done by a GGG (gorilla, garage, gunsmith). The threads on the front of the gas tube were tapered. They took the gas tube off without taking the pin out.
The solution was to expand the tube back out. At first I used a tapered dowel to try it . The threads tightened up. Next I grabbed my transfer punches(toolmakers use these to transfer holes. They are 0.002 smaller than nominal size (ex. 3/8" = 0.375. Punch dia. 0.373. harbor freight sells for $8.00 or $9.00) and found one that was just a little tight. We pressed it in about 3/8 inch to 1/2 inch in and drove it back out. This should be done with a little grease or at least some oil. I did it dry and had to use a Vee block in my 4 inch vise with soft jaws to drive the punch back out. Then I put in service loctite on the threads to help seal them. I had to do this on my M1A gas plug as it kept coming loose after I fired a few rounds. I could see the threads when I put the gas tube pin back in. I checked the tube when I got home and found after firing and found it to still be tight. The gas vent hole is clear but I did not try to size it.
The Results. I fired 25 or 30 rounds of R1M1 ball (So. African). Yes I broke out the good stuff. These fired and functioned flawlessly. Next Malaysian MG ammo 30 rounds. Also fired flawlessly. Last OFV 30 rounds. I had 3 failures to reload and 1 feed ramp jam. I would have expected OFV to have functioned flawlessly as well in a L1A1 as India is a Commonwealth nation and L1A1s were used throughout the Commonwealh. Maybe I have sub standard ammo or this L1A1 just does not like OFV. I could still have other problems but at least the weapon functions right with some kind of ammo. We still have not had the headspace checked or other suggestions that were made. Of course I would expect a little break in on a newly assembled weapon (sorry. Ex service. We dared not call our M16 a gun. This is our weapon, This is our gun....... force of ingrainned habit. Liberals beware WE ARE YOUR WORST NIGHTMARE!!!)
Questions, comments, further suggestions. Please Advise.

Later

Merrden

chromestarhustler
June 23, 2007, 16:00
when you shot the ofv did you increase the gas setting?

merrden
June 23, 2007, 16:39
All rounds were fired at max closed setting.

Merrden

merrden
July 31, 2007, 13:53
Hi Guys: We finally got around to checking the gas port size. I opened it up to 0.113. Test fired at the setting of 5. R1A1 fired flawlessly. OFV fired ok but wanted to jam at the feed ramp sometimes. OK so we need to close the gas regulator a little to get the bolt back a little more so it has more force pushing the next round into battery. Most of my present problems seem to be solved for now. Going back through the parts checking for proper compliance parts is now is the most important task.Since someone else built the piece we do not know if they were honest enough to make sure it was compliant with the law. I found a flash hider but now need to get my barrel threaded to accept it. Do we need to disassemble it and put the barrel in a lathe to cut the threads? I need the right specs for a Brit L1A1. Please advise.

Later

Merrden

merrden
October 07, 2007, 01:05
Hi Guys: we thought we had it licked but still have some problems but now with reloads. I am using RCBS small base dies on a Dillon XL650. I have stoned the feed ramp cone toward the receiver brow until there is almost no flat left between the receiver and the cone. The projectile point seems to barely touch the feed ramp but stops if the bolt does not go all the way back even on hand feed and sometimes when firing. If I pull the bolt back 2/3 - 3/4 back with out ejecting it will chamber the round completely and fire.. Military rounds will zip up the ramp if the bolt will pick the round up and out of the magazine. Please advise.

Later

CFS

chromestarhustler
October 07, 2007, 03:09
check your oal. reloads compared to whats working.

ggiilliiee
October 07, 2007, 11:27
if the round is lodged under the rails when it jamms ..ya gotta open up the rails .the idea is to let the ammo come out of the mag first ...before you try to chamber it ...your doing the wetsack stomp now .(or formerly known as the dragging the dead pig thru sand .)...when mine push the rounds base to the wide part of the mag...the round falls out of the rifle ..if it was inverted ...and they run twice as fast this way ..
a test for my builds is t (ful mag) run bolt face up to first rounds base ....just let it touch the base ...and let go of the charge handle ...if it doesnt put the round in fluidily and at light speed ...you got wetsacked ...and ya need some work ....