Mav .25, I'm at 150 and 135, AEA 33.9's at 940 with a 700mm barrel, 26gr RMR hybrids at 1040fps, I'd say you can turn the HSA in all the way then back out 2.5 turns, 2.5mm that's a good starting point, make 1/2 turn moves until it goes nuts, then back off 1/4 turns then start with little tiny...