Abstract: The present disclosure presents a modular bolt action rifle system having an upper receiver assembly an upper receiver assembly comprising a bolt carrier group assembly; a fire control system; a magazine well; a barrel assembly; and a handguard assembly; wherein the upper receiver assembly is releasably attached to the fire control, the magazine well is releasably attached to the upper receiver assembly, and the barrel assembly is releasably attached to the upper receiver assembly.

Abstract: Various embodiments of manufacturing pistol frames are described. According to various embodiments, a left pistol frame portion is fabricated. A separate right pistol frame portion is also fabricated. The left pistol frame portion is attached to the right pistol frame portion to form a pistol frame.

Abstract: Various embodiments of multi-caliber machine gun systems are described. A multi-caliber machine gun system can include a receiver assembly, a first ammunition feed tray, and a second ammunition feed tray. The first ammunition feed tray can be configured to removably attach to the receiver assembly and to feed a first type of ammunition to the receiver assembly. The second ammunition feed tray can be configured to removably attach to the receiver assembly and to feed a second type of ammunition to the receiver assembly. The receiver assembly can be configured to fire the first type of ammunition when the first ammunition feed tray is removably attached to the receiver assembly. The receiver assembly can be configured to fire the second type of ammunition when the second ammunition feed tray is removably attached to the receiver assembly.

Abstract: Various embodiments of multi-caliber machine gun systems are described. A multi-caliber machine gun system can include a receiver assembly, a first ammunition feed tray, and a second ammunition feed tray. The first ammunition feed tray can be configured to removably attach to the receiver assembly and to feed a first type of ammunition to the receiver assembly. The second ammunition feed tray can be configured to removably attach to the receiver assembly and to feed a second type of ammunition to the receiver assembly. The receiver assembly can be configured to fire the first type of ammunition when the first ammunition feed tray is removably attached to the receiver assembly. The receiver assembly can be configured to fire the second type of ammunition when the second ammunition feed tray is removably attached to the receiver assembly.

Abstract: A modular rifle includes an upper receiver assembly and a barrel assembly. The upper receiver, typically fashioned from aluminum, can be strengthened by insertion of a hardened metal liner insert inside the aft portion of the upper receiver. The upper receiver liner insert is secured within the aft portion of the upper receiver assembly by engaging screw threads on the liner insert with receiving threads inside the aft portion of the upper receiver and insertion of anchor pins into the aft portion of the upper receiver. The anchor pins impinge the liner insert such that it is prevented from rotating within the upper receiver. The barrel assembly is attached to the liner insert by engaging screw threads on the liner insert with threads within a barrel nut connector sleeve.

Abstract: In embodiments, a modular rifle includes a lower receiver assembly, an upper receiver assembly housing a barrel, and a coupling mechanism. Upper receiver assembly has two portions, an aft portion and fore portion, commonly comprising a hand guard. The barrel is releasably attached to the upper receiver first portion by a hand-tightenable barrel nut sleeve connector. Upper receiver second portion is both releasably attached to the barrel nut connector sleeve and to the upper receiver first portion to prevent the barrel nut connector sleeve from rotating during firing of the rifle and to keep the second portion from detaching during firing of the rifle. Attachment of upper receiver second portion to the barrel nut connector sleeve is accomplished by a removable take-down pin and common screw clamp, which secure the barrel nut connector sleeve. Upper receiver first and second portions are connected by an attachment tab and receptacle.

Abstract: In embodiments, a modular rifle includes a lower receiver assembly, an upper receiver assembly, and a coupling mechanism. The upper receiver contains a bolt carrier and a housing enclosing the recoil spring and rod. Within the housing is a counter bore shoulder against which the recoil spring rests. Integrated into the top face of the bolt carrier are compartments, upon which the housing is mounted. Holes in the front of the housing and the upper receiver assembly accommodate the rod. Containing the recoil spring and rod within in the housing mounted to the bolt carrier allows the modular rifle to have a folding, collapsible, or otherwise non-fixed stock. Attached to the rod is a retaining tab, the depression of which allows for the release of the upper receiver from the lower receiver for disassembly of the rifle.

Abstract: A modular rifle includes an upper receiver assembly and a barrel assembly. The upper receiver, typically fashioned from aluminum, can be strengthened by insertion of a hardened metal liner insert inside the aft portion of the upper receiver. The upper receiver liner insert is secured within the aft portion of the upper receiver assembly by engaging screw threads on the liner insert with receiving threads inside the aft portion of the upper receiver and insertion of anchor pins into the aft portion of the upper receiver. The anchor pins impinge the liner insert such that it is prevented from rotating within the upper receiver. The barrel assembly is attached to the liner insert by engaging screw threads on the liner insert with threads within a barrel nut connector sleeve.

Abstract: In embodiments, a modular rifle includes a lower receiver assembly, an upper receiver assembly housing a barrel, and a coupling mechanism. Upper receiver assembly has two portions, an aft portion and fore portion, commonly comprising a hand guard. The barrel is releasably attached to the upper receiver first portion by a hand-tightenable barrel nut sleeve connector. Upper receiver second portion is both releasably attached to the barrel nut connector sleeve and to the upper receiver first portion to prevent the barrel nut connector sleeve from rotating during firing of the rifle and to keep the second portion from detaching during firing of the rifle. Attachment of upper receiver second portion to the barrel nut connector sleeve is accomplished by a removable take-down pin and common screw clamp, which secure the barrel nut connector sleeve. Upper receiver first and second portions are connected by an attachment tab and receptacle.

Abstract: In embodiments, a modular rifle includes a lower receiver assembly, an upper receiver assembly, and a coupling mechanism. The upper receiver contains a bolt carrier and a housing enclosing the recoil spring and rod. Within the housing is a counter bore shoulder against which the recoil spring rests. Integrated into the top face of the bolt carrier are compartments, upon which the housing is mounted. Holes in the front of the housing and the upper receiver assembly accommodate the rod. Containing the recoil spring and rod within in the housing mounted to the bolt carrier allows the modular rifle to have a folding, collapsible, or otherwise non-fixed stock. Attached to the rod is a retaining tab, the depression of which allows for the release of the upper receiver from the lower receiver for disassembly of the rifle.

Abstract: In embodiments, a modular rifle includes a lower receiver assembly, an upper receiver, and a coupling mechanism. The lower receiver assembly that can be separated into a lower receiver portion and a magazine well portion. The coupling mechanism is configured to releasably couple the portions of the lower receiver assembly together. The coupling mechanism including an aperture and a pin that can be moved into and out of the aperture. The upper receiver is releasably coupled to the lower receiver assembly.

Abstract: In embodiments, a modular rifle includes a lower receiver assembly, an upper receiver, and a coupling mechanism. The lower receiver assembly that can be separated into a lower receiver portion and a magazine well portion. The coupling mechanism is configured to releasably couple the portions of the lower receiver assembly together. The coupling mechanism including an aperture and a pin that can be moved into and out of the aperture. The upper receiver is releasably coupled to the lower receiver assembly.