In 1911, Turkey established gun control. From 1915 to 1917, 1.5 million Armenians, unable to defend themselves, were rounded up and exterminated.
In 1929, the Soviet Union established gun control. From 1929 to 1953, about 20 million dissidents, unable to defend themselves, were rounded up and exterminated.
Germany established gun control in 1938 and from 1939 to 1945, a total of 13 million Jews and others who were unable to defend themselves were rounded up and exterminated.
China established gun control in 1935. From 1948 to 1952, 20 million political dissidents, unable to defend themselves were rounded up and exterminated
Guatemala established gun control in 1964. From 1964 to 1981, 100,000 Mayan Indians, unable to defend themselves, were rounded up and exterminated.
Uganda established gun control in 1970. From 1971 to 1979, 300,000 Christians, unable to defend themselves, were rounded up and exterminated.
Cambodia established gun control in 1956. From 1975 to 1977, one million educated people, unable to defend themselves, were rounded up and exterminated.
In JUST the last 100 years, we have this number: Defenseless people rounded up and exterminated in the 20th Century because of gun control: 56 million.