I am in the ammo, training, practice camp and also the .22 version of your current gun camp. Other than .22 stay w/ 9mm. Look at any ammo source and note that .40 or 45 is usually nearly double the piece of 9. Buy ammo in 1000rnd cases. Look at ammoseek if you don't have a local store handy so you get an idea of what you should pay.