Whats the biggest caliber and in the best make and model that is still good accuracy at say 50 yards?
Career makes an airgun in 9mm (Korean air gun). Now, those 9mm pellets are not nearly the same weight as a 9mm handgun bullet, but they are pretty hefty for an airgun - can be used for hunting game. Quackenbush makes a .50 caliber air rifle; again, I don't know the grain of the actual .50 cal pellet. http://www.quackenbushairguns.com/bandit_1.html