A schematic of your Heckler & Koch roller-delayed blowback system The HK21 is usually a selective fire roller-delayed blowback-operated firearm which has a semi-rigid locking mechanism built to retard the rearward motion from the bolt. This hold off was achieved by artificially escalating the inertia with the bolt by making https://jaredrgrbj.dsiblogger.com/55782258/the-5-second-trick-for-hk