Welcome to today’s program photo of the Day! Here we have where it all started for one of the biggest names in guns. This is the Heckler & Koch HK4, the first pistol H&K ever produced. They had made a name for themselves in the early 1960s by transforming the roller-lock CETME into the G3 battle rifle, and the pocket pistol was the next logical step into the commercial market.
“4” is not random. This little blowback gun can be chambered for four different cartridges: .22 LR, .25 ACP, .32 ACP, and .380, and swapping between them takes nothing more than a new barrel, recoil spring, and magazine. Going from a centerfire caliber to a rimfire .22 meant an extra trick: You opened up the breech face and turned it around so that the firing pin lined up with the rim instead of the center. This is a smart move for such a small gun.
There’s a good reason it’s sold in Europe. Many countries have limits on how many guns you can own, and a pistol that is four calibers is considered one. The design relied heavily on the old Mauser HSC, which makes sense; The founders of H&K were former Mauser men, and Alex Seidel, who led the HK4, designed the HSc himself. It never caught the Walther PP, but it got H&K into the pistol game.
Most of our POTDs use images of our friends Rock Island Auction CompanyMajor firearms auction in the United States. Take some time to browse them current auction – Who knows, maybe you’ll find a piece of history to take home!
“Heckler & Koch Model HK4 Semi-Automatic Pistol with Box.” Rock Island Auction, www.rockislandauction.com/detail/5032/1204/heckler-koch-model-hk4-samiautomatic-pistol-with-box. Accessed 25 June 2026.
