A specific "watch-out" I'd offer to the OP, in this type of thread, the overwhelming majority of folks who offer advice have never actually done any handgun hunting. Handgun hunting isn't common, so relevant experience in handgun hunting isn't common. Lots of guys have opinions, but most guys posting in this type of thread are usually like NASCAR fans trying to offer throttle advance advice to Jimmy Johnson...
I was on the phone this morning with a buddy who rebuilt his G20 10mm with a 6" barrel, specifically for hunting pronghorn in WY. He runs a stalking decoy mounted to a bog gear bipod, crouching behind the decoy, firing from kneeling. I know he's using a frame mounted optic, and I know he had a Matchdot on top in the past, but we talked last year about putting an FX-II 4x on top, not sure if he did for this season or not. Getting it done with a pistol is more difficult than a revolver, but largely because you're talking about big, fat bullets with poor sectional density, and relatively small case capacities and low muzzle velocities. The 10mm kills about the same as the 357magnum - tapping out about 75yrds. But at 75 and under, it's serviceable.
Think about real world application for what you're asking - Autoloader preferred... Maybe 10mm... Maybe Dan Wesson... Maybe a revolver... big game hunting...70yrds... remaining applicable for bear defense...
I've been looking at auto loaders for hunting with pistol, I have found 10mm to be very popular . Dan wesson in particular. But i have also seen some revolvers out there. what else is out there that's reliable and holds multiple rounds? Used for defense or big game dangers, as well, hunting big game within 70ish yds max shot.
Name you caliber and firearm of choice.
If you're talking 70yrds, irons can work, but optics are uplifting. You'll benefit from either a red dot or a scope, and from either planning improvised field supports, or carrying one. A scope will be problematic for defensive application - but a guy can remove the scope when in bear country, or a guy can use a red dot, which will be more of a challenge at 70yrds, but faster for defensive use. So that's what you're facing - either some optic, or planning a lot of practice to be very proficient with the irons. A guy can remove a scope and replace the iron sights, or swap to a red dot easily enough. Lots and lots of options for mounting red dots or scopes on pistols or revolvers, so that's pretty easy.
Defensive application also precludes the use of a specialty pistol like an XP100, Striker, Contender, or Encore, or really any of the 8 3/8", 9.5", 7.5" revolvers... A lot of things can work, but the 5-6" revolvers & pistols do lend themselves to defensive use better than the longer pistols.
For 70yrds and under on whitetail sized game, the 357mag and the 10mm are really the basement level for power, but they'll get it done. I've taken whitetails with a G19 and with a 40 S&W Highpoint carbine - both as "prove the point" experiences, not "year in, year out" firearms - those both work if a guy is judicious with shot selection for range, angle, and placement.
So a G20 with a red dot would be a very serviceable option, especially given a field support resource in one flavor or another.
Whatever you buy, pick up a target style 22LR pistol like the Ruger Mark IV/S&W Victory/Browning Buckmark, mount your optic on it (or a duplicate) and shoot it at your max range as much as possible. Doing so is the easiest and cheapest way to cheat your way into a solid shooting skill at longer range shooting with pistols, and there's a distinct reality, if you can't hit it with that 22LR reliably, you're not going to do any better in the field with the "A game" pistol.
You can find multitudes of squabbles on that.
