I put about 60 rounds through mine today ,and Mike I agree, it is really nice. I only own low end pellet guns RWS Diana 34 and a crappy Gamo 177, don't even remember the name, both spring guns and the BSA is a different animal. Shooting in the backyard at 25 yards and I am not an experienced air gunner like most here, but I was grouping 3/4" at 25yards first time out. I'm sure that will improve. My son put 10 shots in the same ragged hole, must have been almost 1/2" and he's shot less than I have (but has better eyes!) so I think the gun would be very accurate in experienced hands.
My two stacked o-rings are still performing, I filled the gun again after the shooting session to about 200 bar and will check it tomorrow to ensure it hasn't leaked down but so far so good. I think I am going to lave the double stacked o-rings alone for now. They are working so why prolong my agony by screwing with it?
Only funny thing is that the gun at 25 yards is destroying my diy pellet trap. I sloped the back of the trap at 45 degrees and used two layers of ptfe cutting board on top of 3/4" plywood and the cutting boards are getting beat to death! These ain't your fathers air rifles!