The murder rate for Greenland, Russia, and Ukraine (all hold restrictive gun laws) sit at 5.31, 6.20, and 8.21 respectively. All significantly higher than the U.S. with a murder rate of 4.96.
Further, Mexico only has one gun store in the entire country, but has a murder rate at 29.07.
Moreover, the death rate from mass shootings per capita between 2009 and 2015 saw that Norway, Serbia, France, Macedonia, Albania, Slovakia, Switzerland, Finland, Belgium, and The Czech Republic had death rates higher than the U.S. from mass shootings between this period.
The murder rate in Britain actually increased after the imposition of restrictive gun laws. The murder rate in Australia remained unchanged after their sweeping gun bans.
Formalized research shows gun laws do not equate to a reduction in crime.
Your understanding about guns seems to be based on the post hoc fallacy.