One little note on the "no handguns 'til 21" rule idea... If you sell handguns, it's not a bad idea to let 18 year olds bring their handguns out if they've got 'em. Why? 'Cause then they might buy their first brand new one from you.
...or from someone else that doesn't treat them like second-class shooters. Just sayin'.
...or from someone else that doesn't treat them like second-class shooters. Just sayin'.