I just picked up my new DPMS AR-15 today, and it fired off 120 rounds just peachy, absolutely no malfs.  (3 new (to me) Colt 30 round mags, and I was afraid one or more of them would require tinkering, but I was wrong.)  After I got done cleaning, I was noticing that the bolt carrier didn't move perfectly smoothly back into battery, and in fact, if I let it forward slowly enough, it would hang up, ON THE HAMMER!

Doesn't cause any problems when firing or cycling at full speed.  Is this normal/OK?

That's perfectly normal, I bet you were doing dry fire drills weren't you?

I was doing the same  and was trying to see far the carrier had to go back before it cocked the hammer and to my dismay I "jammed" my rifle [:P]

It's perfectly normal, just pull it to the rear and let her fly. [:)]

I was just idly jacking the charging handle, you know, the typical behavior when you got a new toy.  :)

Thanks for the reassurance.

Yeah, this is due mostly to having an AR15 carrier and not an M16 carrier.  The latter has a completely covered firing pin when the bolt is all the way to the front (unlocked), and the rear of the pin is exposed when the bolt is in the rearward position (locked) so that the hammer can hit it.
The former has material removed so that if you try to make the gun go full-auto by...say...removing the disconnector and letting the bolt follow the carrier home, the exposed firing pin collar will catch on the bolt.  As an aside, removing the disconnector isn't really likely to make the gun fire full-auto.  Not enough force on the firing pin from the hammer.

The AR15 carriers are a pain in the butt because sometimes if you're trying to be quiet and ride the bolt home, the top of the hammer will "bump"  over the firing pin collar and slow the carrier down enough to keep the bolt from locking closed.  That's fine if you have a forward assist, but it's annoying if you don't.

*Pets his Forward assist*

There is a solution, if the hammer in your rifle has a notch cut on the top front surface.  Get an M16 hammer, cut the little tit at the back off of it (it'll take a grinder to do it) and your "catch" will be gone.  

Actually, all the manufacturers seem to be doing away w/the cutaway carrier and notched hammer anyway. Colt started the trend, just like they started the cutaway carrier/notched hammer crap 35+ years ago. Bought a DPMS complete lower several months ago, and it came w/an unnotched hammer. In fact, the wider disconnector ridge on it told me that it had started out life to be an M16A2 burst fire job.

I had the same problem.Read this thread [url]http://www.ar15.com/forums/topic.html?b=3&f=66&t=168933[/url]