Nov 4, 2025

US12460907 - Light weight ammunition and firearm systems

A firearm system includes a bolt carrier with an internal cavity, a piston disposed within the internal cavity, a forward configuration where the piston is in a forwardmost position relative to the bolt carrier, and an aft configuration where the piston is in a rearmost position relative to the bolt carrier. The piston slides forward and aft relative to the bolt carrier. In the forward configuration, the entire piston remains disposed within the bolt carrier.

Inventors: James Matthew Underwood, Larry Cullen Underwood
Filing date: 2022-12-21

firearmammunitionlightweight

The patent describes a lightweight firearm system featuring a bolt carrier with a piston that can move between forward and aft configurations, allowing for efficient operation. It also introduces primerless ammunition with a unique cartridge design that includes a rear cavity and a thin rear membrane, enhancing performance and reliability.

Claim 1

1 . A primerless firearm ammunition comprising: a cartridge case comprising a rear face, a rim configured to interface with an extractor of a firearm, a rear cavity recessed from the rear face, and an internal cavity; a bullet disposed at least partially within the internal cavity, wherein: the rear cavity remains open to a rear side and empty; a rear membrane separates the rear cavity from the internal cavity; the rear membrane is thinner than all other portions of the cartridge case; and the rear membrane is a continuous barrier between the rear cavity and the internal cavity. a cartridge case comprising a rear face, a rim configured to interface with an extractor of a firearm, a rear cavity recessed from the rear face, and an internal cavity; a bullet disposed at least partially within the internal cavity, wherein: the rear cavity remains open to a rear side and empty; a rear membrane separates the rear cavity from the internal cavity; the rear membrane is thinner than all other portions of the cartridge case; and the rear membrane is a continuous barrier between the rear cavity and the internal cavity.

Google Patents

https://patents.google.com/patent/US12460907

USPTO PDF

https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/12460907