Problem W/ RRA

[WayneS]

 Got my new to me, RRA AR with the heavy 20" BBl. I used Sierra's AR data, at the range none of my loads would fully cycle, striping a new round from the Mag. It would eject.  The Max load for 77 gn bullets in the manual is 23.6  H 4895. Today I loaded 2 rounds, one with 23.8 & 24.0 H 4895. both failed to cycle the bolt back far enough to lock open.  The primer on the 24.0 load is still very round.
I have a load off an internet site that lists 24.5, but I'm a bit leary of going that high in an AR.

[Ranger99]

tried any factory fmj rounds
just for grins?

[WayneS]

RANGER,
 I just tried a  FMJ round, head stamp L C 72, same thing, it would not lock the action open. Looks like the upper is headed back to RRA

V/r

Wayne

[Old Syko]

Wayne you've most likely got a magazine problem as the empty mag is what allows the stop to engage.  Make sure without a mag in place the stop can be manually moved into place to hold the bolt open.  Put in an empty mag, pull the bolt and it should lock open.  If not you have a mag problem. 

[WayneS]

  The problem turns out to me a mis aligned gas block. All should be good for some load development testing at the range next week.

[PAHUnter04]

I was just going to say check your gas block alignment. Also sometimes the the gas block hole in the barrel is drilled to small. I have a Colt 6329 that had to be drilled out to a larger size to function properly.
 
You can check the alignment by the blow back of power around the hole. If it isn't centered its not getting enough gas to cycle the bolt.
 
Regards Jim P.