Quick update on the Grendel saga. Shot with @DuneShoot on Saturday and couldn’t get the Grendel to cycle properly despite changing buffers, BCG’s, magazines. Looked closer at the gas block a little later and as it turns out there are a few more set screws.
Contacted the previous owner to see if he could remember what gas block it was and he couldn’t but Google image search turned up the matching Seekins gas block.
Went back out yesterday and @DuneShoot helped with some trouble shooting and after some adjustment the gun cycles the way it should.
Fully closed gas set screw, opened a full revolution and then two more quarter turns.
Bolt only partially locked back after rapid successive fire (3 round bursts).
Added an 1/8th turn and then a second 1/8th turn. Cycling the way it should finally.