From Reason:

According to gun prohibitionists, Europe is much safer than the United States, because Europe has stricter gun control. In fact, the historical record shows that excessive gun control (as in Europe) is about a hundred times more deadly than “insufficient” gun control (as, supposedly, in the U.S.). While a lone criminal with a gun can be very dangerous, a criminal government with a disarmed population is the deadliest thing on Earth.

In Europe in the 20th century, governments killed about 87.1 million victims, according to research by the late University of Hawaii political scientist R.J. Rummel. That figure does not include combat deaths, such as in World War I or II. It includes only the murder of civilians, from 61.9 million killed by the Soviet Union to 20.9 million killed by Germany. Over the long run, one’s risk of being murdered is much lower in the United States than in Europe. It’s no surprise that migration between the two has always been very heavily in one direction!