[ahole]

The 223 is not baned as it is not classified as a pistole round. nether is the 7.62x39 yet the specialty ammo is prohibited for import. The 7.62x51 aka 308 is classified as a pistol round the intelligent people at the BATF. TC, Remington, Lone Eagle, Savage, H&R... all make a pistol that shoot a 308 round and in the early 1990 7.62x51 AP ammo was very plentiful. So they banned the use ownership and transfer of 7.62x51 aka 308. Even though the same companies make the same guns in all other cal. You can still buy sell and own 7.62x39 AP and Lake City ss109 223. the law states AP ammo can not be a pistol round and has to be US made or imported pre 2005.

[ahole]

If you are going to reload 7.62x51 with pulled black tip SOFT impact round from surplus 30-06. You might want to use IMR3031 38.5 gr powder. i think it might give you a 2700 ft per sec and might penetrate a 3 inch plate at 400 yard. but i would not advise doing anything of the sort.

[Oohrah]

Not many calibers escape not being dual classified pistol/rifle. The .223 is both also as there are pistols build on the AR action, and also the Contenders in that caliber. However the AR pistols are marked on the receiver if they are a pistol.
Also many rifle lowers are stamped multi caliber instead of .223.

[ahole]

True but the batf regulations is only lookingat select cal. 223 and 7.62x39 are not on the list yet 308 aka 7.62x51 is.