0.5% of gun murders in 2016 were adults aged 18-21 with rifles and shotguns

Charles Cooke of the National Review destroyed the gun control narrative in a tweet yesterday.

Correct. There were 636 murders with rifles and shotguns in 2016. 13% of that is 82. So 82 murders with rifles and shotguns committed by 18-21-year-olds. There were 15,070 murders overall in 2016, so that’s 0.5% of total. (1)https://t.co/EgDB2qz01x

— Charles C. W. Cooke (@charlescwcooke) March 13, 2018

 These statistics come to light after the Trump administration backed the moving the age of rifle purchases to 21.