That probally would have to be the .50 cal. That's what is choosen by most snipers today and ontop of it, it is the largest caliber that a civilan can get ahold of. I mean sure there might be a longer shooting gun BUT a .50 cal is the only gun out there that does not need a armor peircing round. It is it's own armor piercing round. Matter of fact I don't even think there is a hollow point for a .50 cal.
I think the N-strike Long Shot or Long Strike
That is the National Shooting Sports Foundation. They promote shooting sports. Gun control attempts to prevent ownership of guns used in shooting sports. No gun= no shooting sports.
A shooting iron is a gun.
The question can't be answered without knowing what type of shooting and what "gun" you mean (hand gun, long gun, centerfire, rimfire, muzzle loader, etc..)
by shooting it with a gun.
practice
Gun clubs, shooting ranges
Shooting solder at a special solder shooting range
The Gatling gun.
Depends on where the gun range is.
shooting it with anything is vandalism.
Freedom.