The part you are missing
All semiautomatic pistols that can accept a detachable magazine and have at least
one military feature: threaded barrel; second pistol grip; barrel shroud; capacity to
accept a detachable magazine at some location outside of the pistol grip; or
semiautomatic version of an automatic firearm.
What the hell is this for? Revolver moonclips?
All semiautomatic shotguns that have a folding, telescoping, or detachable stock;
pistol grip; fixed magazine with the capacity to accept more than 5 rounds; ability to
accept a detachable magazine; forward grip; grenade launcher or rocket launcher;
or shotgun with a revolving cylinder.
I can only name one single shotgun that doesn't have a detachable stock and it's not a semi-auto.
All ammunition feeding devices (magazines, strips, and drums) capable of accepting
more than 10 rounds.
?