The SA vz.58 ( Samopal vzor 58 - Submachinegun No. 58 ) is a Czechoslovakian assault rifle designed in the 1950's. Although externally somewhat similar to the AK-47 series of rifles, it is actually a much different weapon, with the internals being closer to those of the German STG 44 (with some differences). Despite firing the same cartridge (7.62x39mm) as the AK-47 variants, no Vz.58 part, including the magazine, is interchangeable with those of the AK-47. Though the term Sa. (which is short for Samopal, which means "submachine gun") is part of this firearm's official name, it is not a submachine gun as most firearms historians use the term. The term Sa. was used for all subsequent select fire weapons that Czechoslovakia built and adopted after their last indigenous design, the Vz.52 semi-automatic rifle (their own version of an SKS rifle).