The idea sounds good, but for me it's just a feel-good thing. I don't go woods walking, looking to kill critters, so there's no practical benefit to handguns and rifles in the same calibers. Not that I don't have some, they just don't give the warm fuzzy feeling I thought they would. I can just as easily take two ammo calibers to the range. If I want a cheap rifle cartridge I'll use .22LR.