M14 Fail to feed

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Petrock

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I seem to be having a constant fail to feed with my M14.

The rifle fires and ejects the casing but does not pick up the next cartridge. I've tried switching mags and ammo but this problem is fairly consistent.

Any ideas or suggestions would be greatly appreciated.

The only mod to the rifle is a Marstar op rod spring guide and a USGI wood stock.
 
Did the rifle have this problem with the original stock and OP Rod guide spring?
If not. Replace with original parts and repeat testing by replacing one new part at a time until problem crops up. Once you've isolated the part then we can try figuring out what is going on.

L
 
I never shot the rifle with the original stock and it is now gone. When I first changed the stock I did not have this issue. I will try my USGI fiberglass stock to see if the issue persists.

I can also change back to the original guide.
 
take off the stock and pull your oprod back and lock it in place, i recommend having an empty mag in the action to ensure the oprod doesn't fly forward.
tilt the barrel straight up and push the gas piston up into the cylinder all the way and immediately remove your finger and allow it to drop.
if the piston drops kinda slowly.... the slower the better but with smooth movement through out it's drop..... you can rule out a piston problem
if the piston just drops with no resistance..... either you need a new piston (a chinese one) or a new gas cylinder. If you have a friend or two with an m14s/m305 borrow thier pistons to check for better function.... if they work as optimally described above,,,,, replacing the piston is probably the answer.

next thing with the gas assembly, if your piston passes the above tests, then we have ruled out a piston/cylinder caused short stroke. So we then, with the barrel pointing up and oprod locked back, take a 1/16 drill rod or back end of a drill bit, and pass it thru the little hole in the bottom of the gas assembly. it should pass clear into the barrel. shine a flash light or bore light up from the chamber and peek down the bore to verify the drill rod has made it clear into the barrel. If the drill rod stops before entering the barrel, check to see that the slotted screw on the side of your gas assembly (spindle valve) is positioned in the open or closed position (vertical or horizontal). turn the spindle valve screw 1/4 turn and retry the drill rod. it should pass clear thru.

check these things and let us know what you find.

there is a step by step procedure for diagnosing the cause of an m14 short stoking that i can walk you through but no sense typing it all out now. short stroking is caused by a few different things but most commonly is a gas assembly issue.
 
Graeco said:
As per M14dr's post, a dirty piston/gas cylinder was the cause of my short stroking. I cleaned mine with a Canadian-tire brake cleaner, lubed it up with white lithium grease as per the M14_Lubrication_Tutorial_with_Pictures_1_.pdf and problem solved.

http://www.allstudies.org/M14+Bolt+Roller.htm
Click to expand...

I'm hoping that it is that simple. I clean the gas system each time we shoot, but that rifle runs approx 80-120 rounds each shoot, once a month or so.
 
Do you by any chance have a recoil buffer in there? I had an m14 that cycled flawlessly until I put a recoil buffer, then it suddenly would be ejecting rounds, but fail to feed the next one.
 
punkrockboy said:
Do you by any chance have a recoil buffer in there? I had an m14 that cycled flawlessly until I put a recoil buffer, then it suddenly would be ejecting rounds, but fail to feed the next one.
Click to expand...

yes, that is a good point as well.
I'll officiially go on record as saying that In my opinion..... shock buffers have NO PLACE in an m14 rifle and are simply a sales gimick hehehe no offense to anyone who sells them ;)
 
A couple of Questions for ya;
  1. Did you mod the stock to make it able to accept the smaller sized op-rod retention tab? (AKA Popsicle meathod?)
  2. Did you make sure that the magazine was properly seated? (It makes an audioable click sound)
  3. Does it do this with the original op-rod or just the Marstar 1?
 
Satain said:
A couple of Questions for ya;
  1. Did you mod the stock to make it able to accept the smaller sized op-rod retention tab? (AKA Popsicle meathod?)
  2. Did you make sure that the magazine was properly seated? (It makes an audioable click sound)
  3. Does it do this with the original op-rod or just the Marstar 1?
Click to expand...

Yes the popsicle stick is in there, looks beautiful.

Yes the magazine is seated properly.

I have not yet switched op rods.
 
Hmmm...
It could be that the notch in your mag isn't ingauding the op-rod properly or it could be the mag/follower issue. Try first to replace the op-rod with the original 1. If this doesn't work try some new different manufactured mag's.
 
Have you done the hammer follow test? Check the stickies. If the stock isn't geometrically right for your receiver/trigger group geometry, it will likely have hammer following problems.

Most likely though, it is the gas system or possibly binding in the operating mechanism.

Have you done the tilt test yet? This would eliminate a binding oprod as the source.
 
Claven2 said:
Have you done the hammer follow test? Check the stickies. If the stock isn't geometrically right for your receiver/trigger group geometry, it will likely have hammer following problems.

Most likely though, it is the gas system or possibly binding in the operating mechanism.

Have you done the tilt test yet? This would eliminate a binding oprod as the source.
Click to expand...

Hammer follow test? I think you're referring to a function test. Yes I do a function test after ever time the stock is removed from the rifle.
 
Petrock said:
?????

The mod (sicle) to hold the op rod spring guide rod pin in place has been done on the stock. Was the first thing I did when I got the stock.
Click to expand...

Yeah, but are you using an aftermarket op rod spring guide, or the original GI-type stamped steel guide?

If you are using an anftermarket one, there could be something wrong with it.

For example, if you use the Chinese operating spring, they fit tight on SOME rods and can cause short-stroking. If you are using a USGI spring or an M1A apring, you should be fine unless the guide itself is somehow out of spec.

I would also take dow nthe rifle, remove the operating spring and try to tilt the upper forward and backward to 30 degree angles - see if the oprod and bolt fall smoothly from open to close and back again. this will tell you if there is any binding issue wrt the bolt or oprod.

finally, make sure as Thomas points out that your gas vent hole is unobstructed and lined up properly with the hole in the barrel. Did you shim your gas system? If not done properly, this can cause a gas vent hole misalignment. Are you running the original gas system and piston? sometimes guys put a better aftermarket piston in a chinese cylinder and the tolerances don't match up.
 
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