Hi,

A while ago I posted that I had a problem with a round failing to feed while the spent casing was failing to extract.  Most problems seemed to have went away when I stopped using one mag in particular, and switched from regular Winchester ammo to Q3131A or M855.  However, the problem has reared its ugly head again.

I have a 16" Bushmaster barrel on a -A3 flattop.  I've used Brit and USGI mags.  At the range, I don't seem to have the problem very often.  However, at carbine matches, the first round jams, and I end up (the first rifle stage of the day) losing points clearing, or transitioning to pistol.  I shoot Q3131A exclusively.  I have perhaps 500 rounds through the gun now.

When I load, I load from the bolt to the rear, and firmly seat the magazine.  I then release the bolt.  When I fire, the first round of the first stage doesn't extract...it's like the extractor grabbed the case, and pulled it mostly out, but the spent case isn't ejecting.  The bolt carrier is almost all the way back (or sometimes is all the way back), and a new fresh round is out of the feed lips, and either on its way into the empty chamber, or in partially.  Sometimes the spent case is above the bolt.  The only unusual marks on the spent case may be a dent from the bolt trying to go forward on it.

I know that aside from mags, I could check the chamber (to see if it is rough), check the carrier key, and check the extractor.  Honestly, I don't know what rough would look like (aside from a large gouge in the metal--which I don't have).  I have access to a smith if necessary, but prefer to know more about my gun and why it doesn't work.

After the initial failure, and clearing, I can shoot the rest of the day with no more problems.  But, because of potential failure on the first round, this rifle will not be a SHTF gun anytime soon.

Thanks,

-Zmeja

Try this to see if this is the problem.  Get a piece of tubing or an O-ring (D-fender clone) that is a little bigger than the extractor spring.  Add the piece to strengthen up the spring and see if you still have the problem.  If it fixes the problem, then change the extractor spring out with a M-4 (black insert) or a Wolf extra power one.  

P.S. You may have to clean up the bolt face and extractor claw a little bit. It may just be that you are getting excessive shaving in the extractor and it is causing the problems.

I would try to down load your mag to 27 or 28 rounds. With only 500 rounds though your rifle, it's most likely still pretty tight and might be a little slow, on the ejection stroke when it's cold. Then again I'm most likely way off.  

Thanks.  I'll try the Defender first.  I've already downloaded as far as 25 rounds, but there are no guarantees on first round success.

One thing that I have noticed is that the bolt in the carrier is kinda tight.  Even with CLP/FP-10, a fully-assembled bolt carrier group (and clean) will extend (when slinging the bolt BCG in my hand) fully only 5 or 6 times out of 10.  Still, I've felt a new gun should work and function with little problem.

I'll report back when I get to the range next.

-Zmeja

Zmeja,

You may want to pull the extractor and check the claw inner gripping face and rim relief channel edges for burs.  When the bolt closes under live fire, any burs will claw/grip into the case and give it a better grip over just the normal loading.