M14 Forum

45R · February 19th, 2012, 01:22 PM

Hey guys I could use some help with a failure to extract issue.

There is maybe 150 rounds through the gun. I have been shooting Lake City with date stamp 01-04. The last two times out I have been getting failure to extract issues. It happens to rounds loading from either the right or left side of the magazine and causes double feeds. (Tried multiple magazines to rule out mag related issue). I can manually extract the rounds if I use the charging handle so I am a bit confused to what the problem is. I thought I was having a issue with the chamber dirty so that was cleaned before my last outing. I am still having the same issue.

I've tried the tilt test and the piston moves freely. I am puzzled and could use some help from the experts. Any suggestions would be appreciated. Its a SA rifle.

Thanks!

45R

MFD · February 20th, 2012, 01:12 AM

Obviously could be numerous things, but at what stage of the 150 rounds did the failure occur. From the start or later on in the count of 150?? First thing I would check is see if the gas plug is torqued/tightened. Sounds like not enough gas to function and if the plug is loose, can cause that problem. Sure others will have suggestions as well.
Might mention that if the plug is loose, retighten and place small mark of white paint, etc., so with quick visual check you can see if the plug as rotated loose.

45R · February 20th, 2012, 08:45 AM

The extraction issues started after ~ 100 rounds. I didn't think it was the gas plug because the op rod was able to cycle back far enough to try and chamber the second round.

If the gas plug is loose on visual inspection will I see carbon/soot around the plug? I'll check for gas plug tonight and report back.

Thanks MFD!

45R · February 20th, 2012, 02:32 PM

Gas plug was nice and tight.....

Anything else I can look into?

SmokyBaer · February 20th, 2012, 04:46 PM

Remove the gas plug and piston then see if an Allen wrench will poke thru the port and into the rifling. This serves two purposes... check for carbon plugging the port or the valve being closed. Hope that helps.

MFD · February 20th, 2012, 05:06 PM

Out of curiosity, are all 150 rounds the same ammo?? Are they reloads, commercial, mil surp, etc.?? As mentioned about the position of the valve in the gas cyclinger, has it been changed, turned, etc.?? What if anything have you done with the rifle other shooting and normal cleaning?? It may well be carbon build up somewhere in the system, but that is a low round count to generate a carbon problem. In cleaning have you cut out any carbon build up in the piston itself(using std. drill bit tools for the two cavities??) Answer is out there someplace, just can't put my finger on it at this time.
Keep asking and someone will come up with the solution and if I think of any other areas, will get back with you. Mr. Art Luppino may well be able to give you professional advise if you were to contact him?? Just a suggestion.

45R · February 20th, 2012, 05:25 PM

The part that puzzles me is that there is enough gas in the system to push the op rod back far enough to push the next round forward. The hang up is that it fails to extract the spent casing therefore causing a double feed.

Could this still be gas system related? The valve is set in the perpendicular position. I will pull the gas piston out and check for carbon build up.

I have been shooting Lake City 7.62 NATO 01-04 ammo. During the last session I shot a mix of the Lake City and Federal 150gr 308 SP. So I have used Surplus and Commerical.

Both type of ammo had issues extracting. One of the Federal casings got stuck that I needed to strike the changing handle with a piece of wood to eject the round. I will check the inside of the piston for carbon build up when I remove the gas plug tomorrow.

I cleaned out the chamber with a brush, lubed the inside rail the bolt rides on, the roller was oiled and I put a few drops of oil on the op rod. The rifle has a total of 150 rounds through it at this time so I have no bothered to check the inside of the piston for carbon.

Could it be extractor tension or tight chamber? How can I rule these out?

donker2 · February 20th, 2012, 08:42 PM

With the double feed problem, your gas system is working fine. You could have a weak extractor spring, but my bet is its a rough chamber.
Polish the chamber and make sure your ammo is clean.

MFD · February 21st, 2012, 04:05 AM

If it is a rough chamber, rough enough to hang up, would think you could see some scratches, marks, shiny spots, etc. on the case itself?? Are there any unusual marks or signs of scratches caused by a burr/sharp edge that may be in the chamber??

DTOM · February 21st, 2012, 07:55 AM

FWIW, all of my M1A's feeding/extracting issues went away when I replaced all the bolt's guts (NOT the bolt itself) with USGI parts. It took 10 minutes to do it and it runs like a champ now no matter what I feed it.

45R · February 21st, 2012, 08:59 PM

I checked the valve spindle. Good to go
I checked the gas hole in barrel. Good to go
I checked the gas piston. Good to go
I checked the bolt.........the spacer that holds the roller was out of its groove...Fixed
I cleaned the chamber...loaded some empty brass to see if it would cause shiney marks on brass....it did. (I thought these marks were from the magazine but they were from the chamber. Strange thing is when running a Q-Tip into the chamber...it didnt pull the Q-Tip.

45R · March 15th, 2012, 09:03 AM

Update:

Rifle was sent to SAI since I did not have the tools to polish the chamber. SAI replaced the extract, reamed and polished the chamber. Turn around was less than a week from the time it was logged into the factory and was put back on the bus.

Will update further when I get the rifle back and shoot it.