45 cal i prefeer but it took me a while to find the right bullet load comboi mean i shot all of them i was getting ready to switch to 50 cal but i found that 150grains pyrodex and 195 grain hollow point powerbelt works very well i dosent leave the best blood trail but if hit in the chest i havent had a deer go more than 70 yards it works i took the top five buck taken with a muzzleloader in new york this year grossed 174 5/8 huge bannana beams and points