Lacy, only the Magazine capacity. Most manufacturers make firearm packages that have 10rd magazines so their pistols can also be sold in state that have magazine capacity restrictions. The pistols are exactly the same but just have 10rd mags included. The pistols will also accept any standard capacity magazines just fine.

A firearm that is 10+1 means the magazine holds 10 rounds plus 1 in the chamber, hence 10+1. The same goes for 15+1 but with a 15 round magazine plus 1 in the chamber. It was my pleasure to assist you.