What size gas port in the barrel? It has been posted on the forum the 20 6.5 Grendel gas port should be .0935. I wonder if you have a really stout ejector spring in your bolt. How difficult is it to depress the ejector?
If you close the gas block completely and fire one round does the bolt unlock or move?
If it were me Id start with the gas block 4 turns out from closed, fire one cartridge and see if case is ejected and bolt locks back on empty mag. If the bolt locks open on empty I might close the gas block one click and see if it locks back on empty. If the bolt doesnt lock back Id continue to open the gas block until the bolt locked back on empty magazine. Once I get the bolt to lock back on an empty mag Id open one more click.
Is it possible the ammo is loaded to max, ammunition could be causing the 1 O Clock ejection. If you were close Id fire a Wolf steel case cartridge and see how it ejects. Wolf 100 grain FMJ steel case has a light recoil impulse in my rifles.
Is it possible the ammo/bullet is jammed into the lands and increasing pressure. If you put a cartridge in the barrel with no bolt carrier and raise the muzzle does the cartridge fall out under gravity. Do you have to push the cartridge out with a cleaning rod?
If you close the gas block completely and fire one round does the bolt unlock or move?
If it were me Id start with the gas block 4 turns out from closed, fire one cartridge and see if case is ejected and bolt locks back on empty mag. If the bolt locks open on empty I might close the gas block one click and see if it locks back on empty. If the bolt doesnt lock back Id continue to open the gas block until the bolt locked back on empty magazine. Once I get the bolt to lock back on an empty mag Id open one more click.
Is it possible the ammo is loaded to max, ammunition could be causing the 1 O Clock ejection. If you were close Id fire a Wolf steel case cartridge and see how it ejects. Wolf 100 grain FMJ steel case has a light recoil impulse in my rifles.
Is it possible the ammo/bullet is jammed into the lands and increasing pressure. If you put a cartridge in the barrel with no bolt carrier and raise the muzzle does the cartridge fall out under gravity. Do you have to push the cartridge out with a cleaning rod?