In my 280 ackley shooting 162 A-Max. I have tried h4831 sc. It was really consistent shot really good under 1/2" with 56g. @2750fps. any more and the primers would flaten. I tried 56.5g of R-22 @. It shot almost as good under 3/4". About the same speed any more and it would flaten primers.I am thinking of trying H1000 or Retumbo. Do you think I could get a little more velocity with them, Just can make up my mind what to try next.