US Patent 10240882 Crush inducing cartridge chamber

A bottleneck cartridge chamber wherein a circumferential relief recess is placed within the shoulder region of the chamber. As opposed to the continuous angled shoulder of conventional cartridge chambers, the proposed relief recess is envisioned as an angular segment of larger included angle than the conventional chamber shoulder angle (thereby creating a compound angle cartridge chamber shoulder region) or a radial recess that would eliminate a portion of the conventional chamber shoulder.