Sep 8, 2026

US12729767 - Armament system with a non-rotating slip-fit labyrinth seal

A stub base seal comprises a non-rotating slip-fit labyrinth seal to provide additional sealing properties. The labyrinth seal serves to capture errant gasses in the event of a partial leakage between the stub base and a concentric surrounding surface and leverages eddy flow effects to induce back flow impingement thereby reducing the flow rate through a leaking cavity.

Assignee: The United States of America as Represented by the Secretary of the Army
Inventors: Ryan Hanc, Francis Sheer, Christopher Kubik, Arhum Mizra, Edward Hyland, Joseph Kurowsky
Filing date: 2024-09-10

firearmammunitionsealgasbackflow

The patent describes an armament system featuring a gun barrel and an ammunition cartridge with a non-rotating slip-fit stub base that enhances sealing against gas leakage. The stub base incorporates a labyrinth seal with grooves designed to capture errant gases and reduce flow rates through any leaking cavities.

Claim 1

1 . An Armament system comprising a gun barrel comprising a static interior surface for receiving and having removed an ammunition cartridge case which forms a slip-fit with the static interior surface of the gun barrel; and an ammunition cartridge comprising a non-rotating slip-fit stub base configured for providing a primary seal against the static interior surface of the gun barrel by expansion of the stub base against the static interior surface, the stub base comprising a cylindrical cup-shaped body having an open end and a closed end defining an interior cavity, a flange positioned at the closed-end of the body and wherein the body is configured to expand outward against the static surface in response to a pressure increase in the interior cavity; and a secondary labyrinth seal defined by an exterior circumferential surface of the stub base, said labyrinth seal further comprising one or more grooves defined by the exterior circumferential surface of the body and extending radially around the exterior circumference of the body and wherein each of the one or more grooves extends into the body at an angle toward the closed end of the non-rotating slip fit seal and does not extend past the exterior circumferential surface such that said exterior circumferential surface maintains a flush face with respect to the interior surface of the gun barrel and the one more grooves do not interact with the interior surface of the gun barrel and wherein each of the one or more grooves has a cross-sectional profile to induce backflow of a gas within the groove.

Google Patents

https://patents.google.com/patent/US12729767

USPTO PDF

https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/12729767