HK4: Heckler & Koch's Multi-Caliber Pocket Pistol
This video provides an in-depth look at the Heckler & Koch HK4, a unique multi-caliber pocket pistol. The description highlights its innovative design allowing caliber conversion between .22LR, .25 ACP, .32 ACP, and .380 ACP through interchangeable barrels, recoil springs, and a reversible breech face. It details the pistol's design origins, influenced by the Mauser HSc, and its production run from 1968 to 1984. While reasonably successful, it never matched the market penetration of competitors like the Walther PP/PPK. The video also mentions its adoption by German customs police.














