AR-15 Issues, suggestions welcome

[bdwarr6]

Hello Everyone,

While many of you don't know me some do, I am mainly a lurker here but have run into a bit of a snag and figured I would ask for some advice.

I cleaned my .223 AR-15 the other day reassembled it and took it out to shoot, loaded the first mag, and chambered the first round manually, boom worked fine, then to my surprise the bolt didn't even try to move back to eject the shell, so I fiddled with it and still nothing shot about 20 rounds this way. I grabbed my friends bolt carrier and stuck it in my gun, and it worked flawlessly. I am wondering what would have caused this, I have checked the tubes and they are fine.

Also I read somewhere if your bolt wont stand up without closing the rings are bad, my bolt wont stand up without closing, however this is a brand new bolt its only got 300 -350 rounds through it.

Its a DPMS Bolt... I know its not the best but it came in the upper.

Anyone have any suggestions, and or know a way I can test to see if its going to work aside from firing the rifle.

Thanks