Sound like a fun venture. You might talk to Ed @ AHR about one of his 585's or 600's. Maybe bigger than you think you want, but remember, you can always down-load the big one but you can't up-load the smaller one. Plus brass availability can be an issue. I make a light plinker for my 600 that uses an 800 gr flat nose over 70grs IMR-4198 with pillow fiber filler for 1500 fps. Low recoil, tremendous impact, very clean, accurate and only 20 fps variance in speed.