alright, if 3 gun is your focus then you must shoot 9mm the ability to store the extra rounds can be key sometimes. If you are new to USPSA, i do not recommend starting with production due to the fact that the reloads can really throw you off and it is a harder division than limited. So if i were you, i would get some TF basepads from Wall for 2 mags on your pistol and shoot at least 3 USPSA matches at limited minor, after 3-6 matches you can then decide to move to production (because by now your skill should be more predictable and therefore you won't miss critical shots that kill your gameplan in production) or then drop some more cash and get a .40 and stick with limited or worse case just keep shooting limited minor. I have seen guys (even happened to me at my first uspsa match with a texas star) shoot their first match with production and even with numerous mags run out!! beside the fact you are so nervous when you start missing, since you only have 10 rounds, everything really goes downhill, opposed to having 19-22 rounds....
shotgun is easy 21 inch M2 send straight to cywrus, no regrets at all..
until then are numerous people that will let you borrow their gear, myself included... regardless whether you have everything or not, be at the next 3gun match at OKCGC 4th sat in july...