I believe that they make two kinds of Ammo for this particular weapon, Armor piercing and a Nato or Ball-full metal jacket. The former is not available for civilian purchase, at least not in the US. The later is, but as PONTIAC pointed out, it's hard to find and expansive.
I also believe that there's only one model for the 5.7x28mm weapon that's available for purchase in the US - could be wrong. The weapon is made by Fabrique National (SP?), which is a high-end manufacturer out of Belgium who makes a couple different weapons systems for the US, including the M249 SAW.
United States: Used by U.S. Secret Service special agents assigned to protective details. Also used by numerous police departments and SWAT teams such as Passaic County, New Jersey and Duluth, Georgia. It is also used in Texas by Brownsville SWAT.