Dont know what the velocity loss is in a Single Six vs Rifle. Here is what I do know... Facing the same delima I went with the Single Six first due to the fact that is gets the job done and its concealable. I have found it to be minute of Bunny or Squirrel at 25 yards without too much practice. Thats good enough here around these parts. If you got the convertible then the the 22 WRM personal defense ammo from Hornady makes for a not to shabby defense weapon in a hand gun since this ammo was specifically designed for use in short barreled handguns and right on par with Hornadys PD ammo in 380 ACP. Not my first choice in defense rounds but its better than 22 LR! Just say...