In Ohio the smallest you can use is .38. I killed a deer with my .45 TC Sencea RB and 40grs 3ff,about 40yrds. Another one was killed with it,my buddys first MLing deer and a real trophy with 55grs 3ff RB, this gun will not shot a long bullet for some reason. WE tried, no avail. This deer was 35yrds. He had it mounted and would of bought my gun if I said yes. I still have it. My grandson(13) took first place in Nov with it at his first shoot. I got it in 83. I took two seconds with it using the .36 barrel. .45 is a wicked groundhog gun. On deer jest don't strech the barrel to much, keep the shots closer. On my other .45 guns I like 70grs 3ff for deer. Dilly