Mostly price just for the practice. I try to shoot a .22 mostly for most practice, but it helps to get something that gives off the recoil as well.

after that I don't care, I go for cheapest cost for practice ammo but build the load safely to something that will closely mimic my carry ammo. that is what I have the gun for...not for fun range time.

for the other guns I just shoot I go with bullets of decent quality that won't break the bank but will preform and give me good accuracy results.