In terms of absolute numbers, these statistics lead to the unavoidable conclusion that popular semiautomatic rifles such as the AR-15 are commonly possessed by American citizens for lawful purposes within the meaning of
Heller.
[…]
Even accepting the most conservative estimates cited by the parties and by amici, the assault weapons and large-capacity magazines at issue are ‘in common use’ as that term was used in
Heller.[]);
Colorado Outfitters Ass’n v. Hickenlooper, 24 F. Supp. 3d 1050, 1068 (D. Colo. 2014) (concluding that statute “affects the use of firearms that are both widespread and commonly used for self-defense,” in view of the fact that “lawfully owned semiautomatic firearms using a magazine with the capacity of greater than 15 rounds number in the tens of millions”)[.]
https://assets.documentcloud.org/documents/3469330/Decision-upholding-Maryland-s-weapons-ban.pdf