failure to cycle..

[tristanhearn]

I have an ar15 carbine ive assembled on a dpms forged lower, bushmaster barrel & upper, and various other parts. The weapon is well cleaned and oiled, and the magazines are all good too. When I fire, the bolt moves to the rear but freezes halfway over the magazine, and freezes. I can finish the cycling manualy with the charging handle, and it doesnt feel stuck at all. it does this with every mag I tried.

Ideas?

oh also...im firing silver bear FMJ and I have one of those 6-position tapco stocks.

im using a heavy buffer from a 9mm upper kit (ive done that before with ar15 carbines...they seem to help with some cycling problems.)

[Rew]

Sounds like you may be having a gas problem. Check your gas tube out real close. Also check the gas rings on the bolt to make sure the gaps are not lined up. Let us know what you find. :)

[tristanhearn]

Well I checked the gas system... the gas tube is straight and the gas rings are 60 degrees staggard like they should be. then I checked the bolt carrier key, and somehow the allen screws were both really loose...i must not have noticed it before but my wife said she did and forgot to mention it :-/ I tightened them up again, but wont have a chance to shoot for another few days, But im almost positive that was the problem.

Why dont we have simpler hobbies like stamp collecting or something? sheesh :P

[Circuits]

yep, loose carrier key will do that every time - did you stake the screws after tightening them to keep it from happening again?

[Epinephrine]

Also, a little blue Loctite helps out too. It wont hold them permanatly if the staking fails again, but it will keep your gun running until you can get a professional staking or a new bolt carrier.

[JE3146]

problem with loctite is it gets weak with heat...... I'd suggest just screwing the F'ers on there as tight as you can and getting them staked...