Can someone help me w/ this?

The bolt would go back, eject the empty case, but then the bolt would snap back on top of the next round, resulting in either ...

1.  Bolt is complete closed, but no round is in the chamber.

2.  The bolt gets jammed on top of the next round.

From what I can see, this can be two problems.  One, the bolt isn't going back as far as it should be, perhaps the buffer tube or the spring.  Two, the "teeth" on the bolt face is worn out.  I took the bolt out last night and inspected it against my Colt (only ~200 rounds through this one), and the teeth look similar.  I cleaned the buffer assembly, it wasn't that dirty either.  Assembled it back together, lightly lubricated, and going back to the range tonight.

Does anyone have ideas or share similar experiences?  TIA.

what ammo are you using?   I've had some ammo that wouldn't operate the system and it would short stroke and do the same thing that yours is doing.   How about your mags,  does every mag fail to function?

I also checked the firing pin retention pin, FYI.

Any ideas?

Quoted: what ammo are you using?   I've had some ammo that wouldn't operate the system and it would short stroke and do the same thing that yours is doing.   How about your mags,  does every mag fail to function?

I've tried the BMI 10 round and 30 round and the Colt 20 round mags, all jam.

Ammo is Sportsman's Guide XM193.

TIA

have you tried any different ammo?

also check your carrier key,  make sure it is tight

I might also remove the buffer/spring and make sure everything is kosher down the tube.  Something may have gotten bent, or some kind of junk down in there.

Good Luck
Doc

One of my bushy M4s did the same thing and the carrier key was loose and believe it or not it was the last thing I tried and sure enough the key was loosing gas pressure. Just holding it and inspecting it you could not see that it was loose but it was so I tightend it up a little and re staked the screws and have never had that problem again and this was also a new gun direct from Bushmaster


Js15

Quoted: One of my bushy M4s did the same thing and the carrier key was loose and believe it or not it was the last thing I tried and sure enough the key was loosing gas pressure. Just holding it and inspecting it you could not see that it was loose but it was so I tightend it up a little and re staked the screws and have never had that problem again and this was also a new gun direct from Bushmaster Js15

Hm ... I took the entire bolt assembly out last night and inspected it.  I'll check again tonight at the range and report back.  Thanks guys.

First thing to check is the magazine catch - try tighting it one turn (you'd be surprised how often this fixes the problem).  Push the magazine release all the way in and turn the magazine catch (other side of the rifle) one full rotation clockwise.

If that doesn't work then you have to check for Short Recoil.  The procedure for diagnosing and repairing short recoil issues starts on page 3-9 of the -23&P.  This helpful manual is available for free from the Downloads section of this site.  Click on the Information button above and follow the links to where you can download TM 9-1005-319-23&P.

Quoted: One of my bushy M4s did the same thing and the carrier key was loose and believe it or not it was the last thing I tried and sure enough the key was loosing gas pressure. Just holding it and inspecting it you could not see that it was loose but it was so I tightend it up a little and re staked the screws and have never had that problem again and this was also a new gun direct from Bushmaster Js15

Went to the range, same thing happened.  Bam, jam, pull bolt back, cock in a new round, bam repeat.

Opened the AR at the range, reinspected the bolt ... tada!!!  Loose carrier key.  Tighted that sucker up and put the AR back together, puppy didn't jam a single round since (200+ rounds later).

Thanks guys!

I had the same problem with my Bushy 5 years ago, when I first got it, (loose carier key), but it was my fault.  After the first firing, upon disassembly, I unscrewed the two bolts holding the gas carrier key to the carrier in order to "clean everything", and got CLP on the bolts and didn't tighten them enough.  They would come loose after about 40 rounds.  Figured it out, tightened those suckers, and haven't had a problem in thousands of rounds.

Great but you need to stake those keys to keep them from comming loose again!!!

Bob