I'd go with the Single Six, barrel length chosen to match carry / use.
I had a S&W 648 for a while and it was decidedly under impressive. Horribly inaccurate with all ammo I was able to round up. Well .. I bought it used and I found out why it was for sale used. Oops.
My current .22 mag is a Ruger Single Six Hunter. It isn't too good with the light weight hyper velocity stuff but it shoots extremely well with the Federal 50 grain JHP load .. like under half inch at 25 yards. It's not horrible with the WW 40 grain JHP stuff either, but don't feed it the CCI +V if you want to be able to hit the side of a barn .. from inside.
Tom
