Patent attributes
A firearm and a jig for modifying or constructing a firearm with a locking magazine release button is provided. The firearm has a lower receiver including a magazine locking pin aperture disposed in an upper surface thereof where the magazine locking aperture intersects with a magazine release button aperture in a side surface of the lower receiver. The firearm also has an upper receiver attached to the lower receiver via a pivot pin, a magazine attachable to the lower receiver, a magazine locking pin inserted into the magazine locking pin aperture, and a magazine release button comprising a recessed locking catch. The magazine release button releases the magazine when the upper receiver is away from the lower and the pin is not in the magazine locking aperture. The button is inoperable when the upper receiver is next to the lower receiver and the pin engages the locking catch.