This came up a while ago on airgun forums, the conclusion is that its performance number is quite well padded to say the least.

It only charges to 800 psi with its modest sized air tank, yet claims can shoot 40 rounds before losing much muzzle velocity which is comparable to .45 acp. In comparison a modern .45 air rifles that charges to 3k psi and shoot much slower (650 fps) can only manage 6 or so full power shots.