An update to my prior review: the hopup in this gun SUCKS. I got a lemon of a spring, too, it was only shooting 330 fps with .25s. The rest of the internals of this gun are fine, but the rubber rod that provides the hop, and the AEG-style hopup bucking are cheap and don't last. Since there's no replacement hopup rods on the market, you'll have to fashion your own. So far I've had no luck.
I still don't know if the hopup issues are fixable, so If I were you I'd shy away from this gun until replacement parts are available.
I've also noticed that the sear is wearing out, just from a couple hundred rounds of test-firing. The aluminum piston is very nice, but the pot metal sear just ain't up to the task. Whoever designed this thing didn't seem to know much about sniper rifles. Too bad, because it's a beautiful gun.
Nice piston and cylinder. Sturdy internals can handle a powerful spring- except for the sear.
Hopup is junky
No upgrade/replacement parts available
Internals not compatible with any other snipers
Sear wears fast
Rating: [2 of 5 Stars!]