Solved: New Grendel build will not lock bolt back

[Dt219]

Details. New 18” mid length gas Shaw barrel, non adjustable block has been checked several times it is lined up with port. The port size best I can tell from home is +-.072. Carbine buffer. The gun will lock back when cycled MANUALLY and pick up next round. Ejects between 3-4 o’clock but bolt will not lock back or pick up the next shell. I do not have a grendel mag have been using a 6.8 mag which shouldn’t cause the bolt not to lock back. Have tried different lowers/buffers. Shooting factory loaded hornady 123 sst. What should I try next, I’m no dummy but no genius either thanks Only 8 rounds have been fired. Fail zero bcg and no gas leaks I can find