Are you hiking public trails with other people around? Conceal something on the small side. Out in the boonies something a little bigger is fine. Caliber? Crap shoot. I'm just fine with a .22 and in many ways I prefer it. In other ways I prefer a .32H&R and in other ways still I'd prefer a .357. Many others have merit too.
I too like the 4" SP101 (and the similar Charter Arms) and would choose them ten fold over a full sized 4" revolver like my Security Six or a S&W for a lot of carry with very little shooting. That's regardless of what cartridge you choose (both are available in .22lr, .32/.327 and .38/357).
Last edited by L_Killkenny; August 18, 2012 at 02:03 PM.