I've shot my Delta in both IDPA and USPSA. Typical mods for both sports would include improved sights, trigger jobs (if necessary), extended thumb safeties, beavertail grip safeties, magwell funnels . . . that's a start. 10mm could be a really great competition cartridge, but the shooting sports evolved away from it, so it's almost never seen. In USPSA, you can make major power factor with .40, so you don't need the extra capability of the 10, and in IDPA, there's no advantage for using ammo more powerful than 9mm, so again, nobody shoots the 10. You can load up some wimpy rounds, say, 180 grains at 940fps for USPSA, and load the same bullet to an even wimpier 800fps for IDPA, though you'll probably have to change to an eleven-pound recoil spring for reliable function. In USPSA Single Stack division, capacity is limited to eight rounds per magazine, so additional capacity is no advantage, but in IDPA Enhanced Service Pistol, the limit is ten rounds per mag, so you will be one round short even if you have 9-rounders. Not a big deal. I shot an entire season with 9-round mags in ESP, and found it was, as often as not, an advantage to start each stage with an even number of rounds in the gun - nine plus one in the chamber - rather than an additional round that caused a lot of reloads to fall in the middle of a target rather than between targets.
