A firearm includes a barrel, a frame providing support for the barrel, and a hand grip. The hand grip may include a hand-grip main body and a first back-strap extension detachably engaged to a rear portion of the hand-grip main body. The firearm may also include a light system, which may include a light and an ancillary light-system component disposed at least partially in the hand grip between the hand-grip main body and a rear outer surface of the first back-strap extension.