ar15 problems

[johnny11]

I have a ar15 which has a cmmg upper and a LAR with a RRA lpk lower. Everytime i shot a round off, the second round that loads jams up. Im wondering if its my carrier or the mags that im using that causes this. Any info will help. Thanks guys.

[telcolineman]

AR's can be picky about mags, Try a few different mags

[daveyshooter]

I had a similar problem with one that I put together with a Stag lower, and a Rock River upper. One of the old hands at the range noticed it and told me that it would just need some breaking in.
He appears to be right. With about 1,000 round down the pipe, it shoots very well now.
Yes, as telcolineman says, above, the mags DO matter.
Some will say, "yea, but if they are built to MilSpec, should all be the same".
That, alone is true. But in the real world, they are different.
Then there's the issue with creep in all of them. So, just to be on the safe side, keep them unloaded when not at the range.
Creep happens to aluminum mags and I hear that some of the Polymer ones experience it also, when you keep the mag loaded for extended periods of time. The pressure of the mag spring puts force on the lips of the mag, and over time, can move them ever so slightly, but enough to ruin your day.

Make sure your rifle is tight. No loose barrel, that is.

AR-15s are designed to shoot right out of the box. Most do. But as in everything else in life, there are some that for whatever reason, present problems. Nothing that can't be fixed.

If you assembled this rifle, check that the gas tube is properly pinned. A lack of gas getting to the bolt could be it.

Good luck.

[johnny11]

thanks for your input guys.