Why the AR-500 Might Just Be the Most Dangerous Rifle on the Planet The AR-500 fires a modified .500 Smith & Wesson bullet, the .500 Auto Max, Kris Osborn · February 27, 2019 Please leave this field emptyStay Updated with Warrior Maven Subscribe for daily military news and updates delivered straight to your inbox. We don’t spam! Read our privacy policy for more info. Check your inbox or spam folder to confirm your subscription.