Can assault weapon characteristics, such as a pistol grip, be placed on a registered semi-auto centerfire .50 BMG rifle that has a detachable magazine?
No. The law provides that a .50 BMG rifle cannot be an assault weapon nor a machine gun. Therefore, while a .50 BMG rifle already registered as an assault weapon meets the requirements for .50 BMG rifle registration, a .50 BMG rifle registration alone does not meet the assault weapon registration requirements.