Ok. I'm looking to purchase my first handgun. I was immediately drawn to Glocks out of what I shot at the range, so thats what I've been looking at. Initially, figured the 9mm would be a logical choice for my first handgun, but recently I shot the .40 and enjoyed the increase in power. At that point, I figured I'd go with the .40, but then I started hearing a lot about conversion barrels, and how, due to this, the 10mm was the most versatile Glock. I never really gave the 10mm a thought because I figured it would be too much power for my first handgun. However, I'm intrigued by what I've heard about it. My main question is the reliability of these conversion barrels. I hear that the .40 can convert to .357sig with just a barrel change, and can convert to 9mm with slightly more effort than just a changed barrel. Apparently the 10mm can convert to .40, .357sig, and 9x25 dillon with just a barrel change. Looks like these conversions are going to play a role in my decision, so I was wanting to get some information on their reliability. Also, what would cheap 10mm range ammo go for on average?