Currently it's the Beeman RX-2 at 1125 FPS in a .177 pellet
The major air rifle manufacturers are Gamo, Crosman, Benjamin, UTG, Daisy, RWS, Beeman, Mendoza, King Arms, Hornady, Beeman, Air Arms, Air Venturi, etcetera.
it all depends on the condition of the rifle.
Beeman usually has the Model number on the side of the barrel by the loading port or on the barrel by the hinge on break barrel rifles.
K-Mart and I have seen them at other sporting-good stores
Beeman makes several good air rifles & guns. I know of 3 different "Sportsman SS" series that shoot .177 pellets And the RS1 Sportsman that comes with 2 barrels .177 & 22. But I know of no Beeman Air Gun called Sportsman. Just the Sportsman Rifle. If you are talking about the RS1, then yes I would have to say it is a good rifle for the price.
If you are asking "WHAT" not "Where" is the most powerful under lever .177 air rifle. Then I suggest the "Hatsan Torpedo 150 air rifle." I comes in at around 1250 FPS where as most of the other under levers fire at around 950 to 1000 FPS. However Under levers are not the most powerful air rifles. The PCP (PreCharged Pneumatic) Class of air rifles are the most powerful air rifles. An "Air Force Condor and the Evanix Rainstorm" fires a .177 cal pellet at 1300 FPS.
I suggest you contact Beeman directly and ask your question: they make several different models. Beeman Co 10652 Bloomfield Ave Santa Fe Springs, CA 90670 Ph: 562-968-5891
Usually it printed on the left side of the breech or barrel.
Air rilfes have been made that will take down large game.
This rifle was made in Germany from 1986 to 1995. In Very good condition it would be worth between $260 to $325
Yes it can provided you can find the .22 barrel. Beeman makes a dual barrel .177 & .22 rifle
If you are asking about a model 1073 Grizzly K2. They started into production in 2010 and are still being sold.