you need tight tolerances for modern ammo, a shotgun, or muzzle loader is more forgiveing. reloading materials are not federally regulated as firearms, you just dont want to have more than 2lbs at a time, or that could bring trouble.

you want to be able to KNOW and SEE the difference between a blackpowder, and a smokeless powder, and what not to put it in.

one thing that would add a lot of friction is if the primers are regulated.

thats the funny thing, felons cant possess firearms or ammo, however you can possess reloading materials, and be fine there until you start actually reloading, then you are in possession of ammo.