Re: anyone build a competition steel pistol?
It depends on which class your going to run. production, limited or open. For production I use my glock 17 for now, and STI edge in Limited. Did fine tuning load development with both, weeding out powders by fouling now. But you really can't go wrong with anything in the STI line. If your of the handy variety you could start out building with an sti frame kit (fitted slide and frame). By no means are they inexpensive but there is a reason why they are so prevalent in competition. I don't play in Open class due to the cost of the game (Example the sti steelmaster is 2900, some of the other guns like jj's are in the 9k range)
My suggestion would be go to a couple steel matches and check out what gear they are running locally in your chosen class.