If the accuracy loads are falling in the 3200-3300 fps range; why not just shoot a 6.5 Sherman? I can and have shot 140 Berger hybrids at 3339 fps out of my Sherman with 64 gr of N570. This was a very accurate load in my gun but a little hard on brass so I dropped the load by 1 grain. You will use much less powder and the recoil and concussion will also be less.