Lightweight machine gun receiver and method of manufacturing

Abstract

A lightweight machine gun receiver has a frame having opposed left and right shell portions configured to separably connect to each other in a connected condition, when in the connected condition, the frame defining an internal space configured to receive a reciprocating bolt, have a barrel connection facility, and have a trigger connection facility, when in the connected condition, the frame being an elongated body having a left side panel having upper and lower edges and an opposed right side panel having upper and lower edges, each of the left and right shell portions having top and bottom spans extending laterally from the associated side panel toward corresponding opposed top and bottom spans, the top and bottom spans having respective free ends having respective top and bottom span mating facilities configured to mate with each other, and the top and bottom span mating facilities each having a sliding interface.

I claim: 
     
         1 . A firearm comprising:
 a frame having opposed first and second shell portions;   the first and second shell portions configured to separably connect to each other in a connected condition;   when in the connected condition, the frame defining an internal space;   the first and second shell portions having respective mating facilities configured to mate with each other; and   the mating facilities each having a sliding interface.   
     
     
         2 . The firearm of  claim 1  wherein the sliding interface is a dovetail joint. 
     
     
         3 . The firearm of  claim 1  wherein the sliding interface is operable to constrain movement of the left and right shell portions to movement only in a vertical direction with respect to each other. 
     
     
         4 . The firearm of  claim 1  wherein the frame defines a frame axis and wherein the sliding interface is operable to constrain movement of the left and right shell portions to an interface direction perpendicular to the frame axis. 
     
     
         5 . The firearm of  claim 1  wherein each of the sliding interfaces includes a junction profile having an articulated shape. 
     
     
         6 . The firearm of  claim 1  wherein the left and right shell portions meet at a medial vertical plane. 
     
     
         7 . The firearm of  claim 1  wherein each of the sliding interfaces includes closely mating cylindrical forms defining a sliding axis. 
     
     
         8 . The firearm of  claim 1  wherein each of the sliding interfaces includes a protrusion on one of the left and right shell portions, and a recess on the other of the left and right shell portions adapted to closely receive the protrusion. 
     
     
         9 . A firearm comprising:
 a frame having opposed interconnectable first and second shell portions;   the first shell portion having a first mounting facility;   the second shell portion having a second mounting facility; and   the first mounting facility and the second mounting facility comprising a sliding interface operable when connected to prevent relative movement of the first shell portion and the second shell portion except in a single sliding direction.   
     
     
         10 . The firearm of  claim 9  wherein the sliding direction is vertical. 
     
     
         11 . The firearm of  claim 9  wherein the sliding direction is perpendicular to an axis associated with a space defined by the left and right shell portions. 
     
     
         12 . The firearm of  claim 9  wherein each of the left and right shell portions includes a major planar sidewall and wherein the sliding direction is parallel to the major planar sidewalls. 
     
     
         13 . The firearm of  claim 15  wherein the left and right planar sidewalls each includes a span extending laterally from the respective left and right planar sidewalls, and the spans each having free ends including the sliding interface. 
     
     
         14 . The firearm of  claim 9  wherein the left and right shell portions meet at a medial vertical plane. 
     
     
         15 . The firearm of  claim 9  wherein the sliding interface is a dovetail joint. 
     
     
         16 . The firearm of  claim 9  wherein the sliding interface is operable to constrain movement of the left and right shells to movement only in a vertical direction with respect to each other. 
     
     
         17 . The firearm of  claim 9  wherein the sliding interface includes closely mating cylindrical forms defining a sliding axis. 
     
     
         18 . The firearm of  claim 9  wherein the sliding interface includes a protrusion on one of the left and right shell portions, and a recess on the other of the left and right shell portions adapted to closely receive the protrusion.