On another note, does 922r even apply to adding extended magazine tubes? Or, if my understanding is correct, since most semiauto berettas and benellis (except the m4) are not on the list, 922r does not apply? I believe M4s have the 922r issue when trying to modify it (usually extended magazine tubes or a collapsible stock) because such modifications would essentially convert it into a "banned" configuration of an imported gun. Or are all imports subject to 922r?