Most of us PPC guys use a modified K or L frame S&W. with heavy barrel &/or underlugs for recoil reduction. Aristocrat or Witchita sights are not needed but are handier as you don't have to count the clicks when changing sight settings for 50yd. I've seen some on EE for around $600. Some now use autos for this match as well, .45's, PPC9's, etc.
If you want to expand into Distinguished Revolver or Dist S/A you'll need a factory/unmodified gun. Trigger jobs & grips to suit are allowed. Trigger pulls are weighed before every match even if the gun just came off the line & is borrowed to another competitor.
Duty Pistol is a whole different ball of wax. The guns must be fixed-sighted, DAO, traditional DA or striker fired only, 1911's need not apply,there's a list of approved guns in the rule book. Min 5 lb trigger pull.Level 2 or 3 holsters, max 4 loaded mags, 1 in gun, 2 snapped in mag pouch, one in pocket.
I personnaly use a modified Mod 10 as comp gun, Mod 14 Dist revolver, 5906 & G-17 DutyPistol. Don't as yet shoot Dist S/A but some guys use their duty gun.
Welcome to the group.