Before I get all smart guy, it's only 3 shots and it was better than the 77's so it's a cherry pick.  OTOH, it's only about the 30th round down the stock 16in. PWS with an untried load--22.5 XBR with Custom Comps, range pickup brass,100yds front bag and bench.  I only try 3 at a time as it's butt cold out and if it's good like this, I'll load some more and go for 5.   So to the naysayers, I don't need a DI to get a nice group. At this point I don't even need another load.  I still have about 5 powder choices, and the almighty Varget to see if it likes 77's. Now I just need to back the target up with more rounds--3 aint so hard, sometimes

Nice

People that think a piston isn't accurate have no idea how they work.  Bullet is gone from the muzzle before the piston moves.  That means no effect on accuracy.  I'm shooting .75moa on average with a Rainier Select barrel, AA Kit, and 69gr SMKs in front of Varget.  I'm pretty happy.