Don't know for sure. Probably because they are "preferred by criminals." They aren't popular rounds for small game/large game or defense so have no "legitimate use" except for killing people. (Sounds a bit like the "assault weapons" argument doesn't it!) It would be easier to pit the "responsible" gun owners against those with these nefarious weapons...you know, divide and conquer. (Kind of like "sportsmen" dividing over legitimate uses for military type rifles.)That's interesting. Why outlaw .32 or .25?