Repost from another thread. It's my idea and I think it's a damned good one:
My proposal is a nationwide, graduated licensing system, possibly with dividing guns into categories of combat effectiveness:
Single-fire hunting rifles/shotguns (including limited-capacity semi-automatic hunting shotguns) being category zero - no licensing requirement; free for all adults to own and carry on condition that the weapon is used in connection with hunting
Concealed carry pistols being category one - a two-hour class, instant background check, and one-time live-fire range qualification
Semi-automatic rifles and non-hunting shotguns being category two - a four-hour class, full background check, and one-time live-fire range qualification
Fully automatic weapons of all classifications being category three - a weekend class, extensive background check, and annual range qualification
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I would repeal all laws banning high capacity magazines and cosmetic features (including short barrels). I would repeal all laws banning incendiary, explosive (Raufoss etc.), armor-piercing, and other specialist ammunition. I would make concealed and open carry for all weapon types legal nationwide and ban gun-free zones (including schools, but I would ban *open* carry in schools). The catch is that you must have the appropriate category license to buy, own, and carry a weapon from that category (but each category of license qualifies an individual to own/carry weapons from lower categories)
This law would pre-empt all state gun laws, but states can opt-out on the condition that they do not enact more restrictive laws in its place.