Suggestions? When I turn 21 im going to apply for a right to carry permit. I am wondering what gun would be good for range practice now, that would make a good carry firearm down the road. Are the slides interchangable in Glocks, especially with different calibers? If so I was thinking along the lines of getting a Glock 19, and then a Glock 32 in .357. Not sure what the opinions are about the .357 either.