hmm, somehow I missed this thread previously... right up my alley
I shoot at MCF&G matches with 45 acp 230 grain rainier plated bullets. To really do the job I wouldn't go any less than 357 magnum. Anything 40+ is reasonable. Some guys are shooting 9mm and 38 spl, but the pins have to be moved to the middle of the table. If you hit it square with the 45, you clear it off the table, no problem. The main thing is to hit the pin solidly, otherwise you just knock it over and then it's hell to kick off the table. It always seems to spin and "point" at you so you have a little 3-4 inch target. Just blast it off the table.