An estimated 1/5th of all firearms in circulation around the world owe their design to Kalashnikov.

You could tally all firearm deaths since 1947, divide by 5 and get a reasonably good estimate.

To get even closer, exclude 95% of suicides and exclude 95% of homicides in the USA (along with plenty of other countries) since killers in countries not at war or in conflict tend to use handguns 20 times more often.