Patent attributes
A lower receiver for an AR15 type firearm is provided comprising a non-detachable magazine movable in the receiver between a first locked position where the firearm is ready for use (i.e. cocked and ready for firing) and a second non-operational position where the magazine is lowered sufficiently to open a window or aperture in the receiver enabling the user to load fresh shell cartridges into the magazine. A locking mechanism also is provided for controlling the position of the non-detachable magazine between the first and second positions. A child-proof lock further is provided to prevent undesired activation of the locking mechanism. Additionally, a novel locking plate disposed between the lower receiver's frame and the receiver's stock extension tube provides enhanced support for the extension tube and an accessory attachment point for a shoulder strap or sling.