Gamo Hunter Extreme 1650 FPS - Air rifle .177 Cal Air Force TalonP 900 FPS air pistol .25 Cal Hatsan AT P1 Air Pistol .177 870 FPS The Air Force TalonP is faster in .25 Cal than the Hatsan .177 Cal
@ 4000 fps or so
Depends on which .50 cal, and which cartidge. If you mean a Barrett Model 82A1 sniper rifle, in .50 BMG, standard ball ammo is ABOUT 2800 fps.
In .22 cal it's rated at 1000 FPS
4/100's of an inch. .50 cal = .5 inch .54 cal = .54 inch
Rodents and small game.
Rodents
It all depends on the particular model and the power system.
50-150 USD
Depends upon charge, barrel length etc, and how far from the muzzle you're measuring it. But around 700 fps is probably a reasonable guess.
Remington didn't make a model 54, Winchester did but not in 22 (that I know of), Marlin model 54 is a shotgun.
1 and 48 twist