The FBI has identified the shooting suspect at the rally of Don the convicted as Thomas Mathew Crooks age 20.
Two things stand out. The identity of the shooter will make it a lot harder for the MAGA Republicans to use their usual racist dog whistles. He was a "Real American".
2nd thing is In 21st Century America a 20 year old cannot buy beer in Pennsylvania (nor in any state as of 1984).
OTOH you can purchase a "long gun" at the age of 18. This includes a typical AR-15 style weapon with a capacity to fire a minimum of 10 bullets. Each bullet has muzzle velocity (speed) of 3,300 ft/s (1,006 m/s).
Nasty and lethal. A weapon of war designed only for mass killing (or assassinating Presidential candidates). And thanks to the 6 Operatives so much easier to purchase.