Quote Originally Posted by Clint45 View Post
Nearly every .22 pistol has a standard magazine capacity of 10 rounds, and many .22 revolvers have 8 0r 9 chambers in the cylinder. Ruger 10/22 comes standard with a 10 round mag, and many tube mags hold even more. I see NO EXCEPTION for rimfires.
I don't get the impression that any aspect of the magazine limit number was an oversight. They very likely tried to figure out a number that would be just low enough to effectively outlaw the vast majority of firearms.