Question: The Ckm wz. 30 was a Polish-made clone of what American heavy machine gun used by the United States in World War I, World War II, Korea and to a limited extent in Vietnam?
Sentence (from "M1917 Browning machine gun"): The M1917, which was used on some aircraft as well as in a ground role, had a cyclic rate of 450 rounds per minute; the M1917A1 had a cyclic rate of 450 to 600 rounds per minute.
Relevant evidence: No