Your the second person recommending the silvertip 175gr. I am leaning toward the corbon powerball for my arena....any good or bad on that ?
The Cor-bon powerballs are excellent. I gave the retired guy I mentioned a call last night and found he's now part-timing as a court bailiff. I asked him if he was using his 10mm as his carry gun [kinda noisy in an enclosed space!] and he said yep, though he now loads with the Cor-Bon 135-grain *for when it's crowded.*
I think in the same situation, I might go with a 1911 in .400 Cor-Bon, but a .45ACP would likely do okay up close- it's when things stretch out to 100 meters or so that a warmish 10mm really shines [same ME as a .45 ACP at the muzzle, and only a 2" drop at 100] These guys have pretty much figured out what can be done with a 10mm, and what works in it, and know more about the subject than I do.
I'm particularly fond of these things in .45, unfortunately not available as loaded ammo in 10mm. But they do make the bullets available, and the 165-grain for the .40 S&W might be just the ticket in 10mm...or for us old dinosaurs who still like the .41 magnum S&W wheelguns.