ALEXANDRIA, Va., June 6 -- United States Patent no. 12,281,865, issued on April 22.
"Mechanical velocity enhancement assembly" was invented by Eddie L Brooks (Tylertown, Miss.).
According to the abstract* released by the U.S. Patent & Trademark Office: "A supplemental propulsion system for a weapon used to fire a projectile includes a barrel and chamber to hold a projectile round. A translating pressure tank surrounds a portion of the barrel, and the pressure tank is configured to translate along the barrel. A recoil spring assembly includes a spring and a pressure plate downstream of the chamber for holding the projectile round. The pressure tank is coupled to the pressure plate such that the spring is configured to stretch upon firing o...