B.I.
There have been many good replies to the question of best caliber for competion.
Personally, when I carry concealed I have a Colt Officers Model in .45 acp. I use matches to practice and finetune my rig. It's a good thing I've had this goal in mind. Shooting a compact with factory loads and six-round magazines is not the way to star in a IPSC match. However, I don't carry a $3,000 race pistol with optical sights under my jacket! In my opinion, one of the questions one should ask is,"Am I shooting to practice with my carry rig or am I in it for the sport?" IDPA is able to provide for both.