The 10.4×38mm Swiss Rimfire is a kind of ammunition used in rifles. In 1867, the Swiss military adopted the 10.4×38mm cartridge for military use. Although it is one of the few rimfire cartridges to be adopted for military service, its 313 grain bullet and muzzle velocity of 1400 fps easily matched the performance of its contemporaries. The most popular arms chambered for this round were the Vetterli series of rifles. This type of round was also used in the 1867 Peabody.
The original round had a copper case and a round nose lead bullet. In 1871, and again 1878, the bullet was replaced with an improved paper patched round. Despite improvements, bullet performance changed very little.