Abstract

A novel rifling is disclosed, wherein a plurality of arc segments are disposed equally about the bore of a gun barrel, when viewed in cross-section. The surface of each arc segment comprises a bearing surface that imparts a spin on a projectile moving down a length of the gun barrel.

IPC Classes  ?

• F41A 21/18 - GroovesRifling

Abstract

A conversion unit for converting an AR-15 style military assault rifle to a submachine gun includes a central assembly having a magazine well and rear barrel mount. The magazine well can be inserted downwardly into the lower receiver of the assault rifle and accommodates magazines for shorter cartridges. The conversion unit also includes a forearm and barrel assembly and an upper receiver with a stabilizing rail. A pressure equalizing gas operating system eliminates the need for a buttstock with recoil spring. An operating rod extends forward from the upper receiver and into the forearm enclosure. The operating rod is attached to the bolt of the submachine gun and engaged with a reciprocating gas cylinder that surrounds the barrel.

IPC Classes  ?

• F41A 11/02 - Modular concepts, e.g. weapon-family concepts
• F41A 9/37 - Feeding two or more kinds of ammunition to the same gunFeeding from two sides
• F41A 9/65 - Box magazines having a cartridge follower
• F41A 3/66 - Breech housings or framesReceivers
• F41A 21/48 - Barrel mounting means, e.g. releasable mountings for replaceable barrels
• F41C 23/16 - ForestocksHandgripsHand guards
• F41A 9/59 - Ejectors for clips or magazines, e.g. when empty