When we think about roller-delayed blowback firearms, we generally think of H&K rifles - but H&K also made a miniature version of the system for the P9 pistol in the late 1960s. The P9 was made as a single-stack design in both 9mm and .45ACP, along with a target version (with adjustable sights) and a suppressor-ready version (the P9S, which is what we have in today's video). The P9 was a pretty good gun overall, and I really don't have any complaints about it after shooting (although the cocking/decocking lever is not necessarily intuitive).