Yesterday, I took my carbine out for the first time.  It is made up of RRA lower with a 6 pos. collapseable stock and a Stag arms upper.  The first problem was that when I released the charging handle it would'nt always load the round into the chamber and I would have to pull it back and release it again for it to load.  this happened several times.  2nd when fireing there was a falure to extract competely and the bolt would return to try and load another fresh round while the spent case was still in the rifle.  To clear it I would have to remove the mag, would clear the out the spent case and the now mangled unfired round.  At the time I was using UMC fmj and winchester jhp both 55 grain boat tail.  I swiched to XM193 and the problem seemed to clear up and only happed twice out of 120 rounds.  When I returned home I cleaned everything and paid close attention to the bolt , bolt carrier,extractor and extractor spring all looked fine.  Could the problem be a weak recoil spring, or a mag that has too much spring force or could my rifle not like weak ammo? Any advice?hinking.gif

No, I wasnt rideing the charging handle.  The Upper is stag arms  and I got the mags from talon arms, I think they were made by D&H with the mag pull follower, and teflon coated.

Oh the upper was assembled by Stag arms

Not fully ejecting or not loading 2nd round is Short Stroking comon on a new weapon until it breaks in. It took mine around 100 rounds, now she is flinging them.

UMC works fine for me. Only ones that have problems with not are WOLF do not load 2nd round and S & B does this every so often like a couple per box.

Quoted: cyling fully to pick up the next round and feeding the live round into the un-extracted case.

uhhh, guess I kinda missed that part. Thats what I get for reading and working.

It's threads like these that make me glad that I have the sense to buy quality guns.

Quoted:
what length barrel?

does the bolt lock back on the last round fired?

your feeding failures could be related to roughness between the carrier and the upper (lube properly) a poor fit between the carrier key and the gas tube (perform the 40 degree check outlined in the 23&P) or your feed ramps could be incomplete or mislocated (verify by eyeball). when the rounds failed to feed in what orientation did they stop?

FtEx are usually made worse by hotter (XM193 v UMC) ammo. I think your extractor is faulty and gets a better grip on the XM193 case compared to the others.

Tweak,

My barrel length is 16" and the bolt remains open on the last round.  You mentioned a "40 degree check outlined in the 23&P, what is that and where can I find it?  The feed ramps compaired to my bushmaster look normal.  When the failure occurs the partially ejected case is out but is tilted slighly downwards while the fresh round is mostly stripped from the mag but not in the chamber , and is usually dented by the partially ejected round in the usually in the area where the case is necked down. When I remove the mag both the fired round both fall down out of the mag well.
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I was unaware the Stag arms or Rock River Arms were not "quality" components, I have in fact heard that these were both reputable makers on this board.

Look here

page 204.

step #4.

Check the sticky "Read this before posting" at the top of the page.

There are links to common problems and fixes for them.   The manual that I referenced you to is also linked there.


good luck.

Thanks, I'll preform the check and get back to you.

I did the check on the gas tube and key and I looked fine, I compaired it with my bushmaster both seemed to have the same tolerences, with no sticking.

It's threads like these that make me glad that I have the sense to buy quality guns.

THAT was a BIG help!!!