Please help !! ,  

I built a M-16A1 clone , i used a M-16A1 upper assy. and a bushmaster lower  ,with AR-15 trig.group.

The problem is that the gun keeps jaming - stovepipe style - with the next live round getting wedged up in chargeing handle , makeing pulling back chargeing handle to clear jam very dificult !

the bolt & carrier are U.S.G.I M-16A1 - the only prob. i can see is the carrier key has a flared out tip-( the part that fits around gas tube) - it doesnot bind on my gun , but appears to have more wear on it than my barrel - as though it was swaped at the retailer from another more used upper receiver assy.
i HAVE TRYED DIFFERENT MAGS , & AMMO -- SAME TROUBLE !

DO you think the problem is the carrier key ? , or the gas rings on the bolt ?

it can get real expensive buying replacement parts - when i cant pin point the trouble area !

PLEASE HELP !!!

If the key opening is flared, your gas tube may be out of line.  Check alignment by slidding the bolt back and forth in the upper with it separeted from the lower.  If it hangs up check the gas tube and replace the bolt carrier. That may be the problem or not.

thanks , it does float smooth , and bolt locks & opens very smooth also - if i can narrow the problem down to replacing a fer parts , this would be great ! - but i have no clue - if it is the key , or any other component of bolt & carrier !

Load one round in the mag, Chamber this round and fire. It should lock open. If it does so then try it again. If it passes this test 100% then you most likely have magazine issues.

If it does not eject the shell then you could have bad gas rings, leaking key, etc.

The most surefire way to troubleshoot is to swap out parts with a know reliable rifle.

good luck
rj

Thanks RJAY !!! ,   IF i can narrow it down to those ,  ill be OK !!!

I have had this problem before it is your extractor  check the spring there should be a small rubber core in the spring Adco sells a small rubber O-ring that increases tension and surrounds the spring.  also check the extractor for dirt or excessive wear.

I don't think the extractor should be the problem.  It sounds like failure to feed not failure to extract.

Do you have GI alum mags or cheapie steel mags ?

rj