Ive worked up from 37gn to 40gn and the rifle is shooting very accurately with 40gn. I'm not sure I will push it anymore. I may try 40.5 and 41gn in the future but right now I'm pretty happy. Shooting 1/2" groups at 100yrds now and 1" groups at 200yrds. I'm very curious as to what velocity I'm getting with this load. Gonna have to get a chronograph asap.