Most people call this IPSC. IPSC is the international governing body of the sport. USPSA is the US group.
USPSA is shot at the Blackwater Practical Shooters matches held on the 3rd Sunday of each month. It is more of a run and gun style of shooting as compared to IDPA. We usually have 5 stages and most months we will be also having 1 side match stage. The side match stage alternates months between shotgun and carbine.
Check out the website for more information.
http://blackwateripsc.exis.net/
USPSA - United States Practial Shooting Association
Moderator: Doc@The-Armory
Pretty much what you can shoot IDPA with you can shoot USPSA with. Yeah..Your holsters need an upgrade...To at least Fobus or Uncle Mikes Kydex holsters. You also have that 1911 that you can use as well. For USPSA you can have stages with up to 32 rounds required in a stage. So you have to make sure that you have enough rounds on you to complete the COF.