Heckler & Koch HK33 In this week’s Armourer’s Bench video I take a look at Heckler & Koch’s first 5.56x45mm rifle, the HK33. Introduced in the late 1960s, the HK33 was Heckler & Koch’s response to the emergence of the new 5.56x45mm round and FN’s introduction of the FN CAL. While the HK33 wasn’t adopted by West Germany it proved a popular export rifle and remained into production into the 1980s.