I've been watching this since the beginning and just about can't stand the amount of fiddling this thing has needed. The whole problem is a gun needs to be headspaced as a unit when completed and not piecemeal. I get the impression the barrel and bolt are done remotely and not to the very gun they're installed in. If you start with a new barrel, you can do it to spec and end this misery. Then you should be able to shoot whatever ammo comes to hand...
AMEN --- Gunsmithing 101 , exactly why new commercial barrels come short chambered ---