Do you need defense from rodents...if not leave the .17HMR for the varmints...and chamber it in a decent rifle. I imagine that the blast and noise will probably be substantial out of a little revolver. I'd rather have a .22LR for defense (not that I consider that ideal either). If you want a wheel gun for SD against bigger foes (like the two legged kind)...the .357Mag. will get the job done with authority (and 5-6 rnds will generally prove to be plenty).
It is probably the most accurate rimfire cartridge available (at least if you exclude the uber-expensive .22LR offerings from Eley and Lapua). It also affords better long range performance on small game and varmints. IMO the only drawback of the cartridge is the relatively high cost of ammunition.
Because for $300 you can buy a rifle that will shoot half-MOA all day long and shoot laser-flat out past 200yds. Ammo is relatively expensive but you ain't gonna be burnin' up a brick or two a range session. It's best as a field cartridge and two $13 boxes of ammo last me a year, or two.
