[Recusance]

I am having issues with my SBR 300 whisper. 10.5 inch barrel.

the pistol length gas port is opened up to 100 thousandths, the buffer is without internal weights. the adjustable gas block is opened almost to the last thread.

I am shooting factory hornady 110 grain rounds

but also I have hand loaded 110 VMAX with 20.2 grains of H-110

150 grain bullets with 20.2 grains of AA1680

and 220 bullets with 15.5 G of AA1680

the gun will only cycle 50% of the time with the 110 and 220 bullets.

and 95% of the time with the 150 G bullets.

none of the loads will lock back the Bolt carrier on last round. works a little better with the suppressor on, but still no lock back.

what should I be looking for to solve my problems?