Jimro said:
Generally I recommend 1x magnification per 100 yards for "tactical" or "hunting" uses.
1x per 100 yards... yikes. I'd take a zero off that for my purposes.
I'm a big fan of "Aim Small, Miss Small". You can't "Aim Small" if you can't SEE Small.
I had a red dot "1"x on my shotgun for one morning (no more than about 2 hours in truth), one deer season. A group of doe came through the woods, walking, at about 70 yards. I simply could not convince myself to pull the trigger. The dot covered what seemed like about 12 inches at that range (even though it was probably less than 3) and there was no way I could tell if there was a sapling or other obstruction between us.
I left the woods, went to Bass Pro, got a Bushnell Banner Dusk and Dawn 3-9x and never looked back. The scope probably never saw less than 5x either, even though the vast, VAST majority of my shots at deer are 40 yards and under. I shot one, on the run, at about 10 feet one day, scope on 5x.
Plus, there's the sighting-in issue. Sighting in a gun at 100 yards with 1 or 2 or 3x (or IMO even 9x) just sucks. Yeah, it works fine for "Close enough to kill a deer" but it's not for precision work or even just finding out how good the gun can shoot.
I don't see why any shooter ever needs less than 3x, and that's only if they're not experienced with optics. An experienced scope shooter should never have any trouble with 5x. Target acquisition problems are a result of improper shouldering of the gun, not a product of magnification. Yes, magnification... well, magnifies... the issues but it doesn't CAUSE them. The cause is bringing your eye to the scope instead of bringing the scope to your eye.
500 yard shooting with the possibility of close shots? A 5-50x would be ideal, if such a thing existed and cost less than a Ferrari.