My gun is a mini-fishbone...but that's irrelevant.
The gun I used said product in is an insanely modified 2000 right-feed, of all things
VERY HEAVY, use it with a very light spring and say bye-bye to chopping
You have to know what you're doing to install/adjust it
Let me explain how this hammer does it's job: the hammer is heavy as Oprah! For a lighter hammer to hit the valve pin with the same force, it would need to use a "hard" spring. The tungsten hammer weighs enough to use the lightest spring I've ever heard of (the "light" spring from freeflow's spring kit). A lighter spring means the lpr can cock the gun using less pressure (35-50 psi on most cockers, as low as 25 psi on freeflow true-bored and arbor-honed bodied guns). The bolt goes forward with the same pressure that it goes back because when you release the trigger the pressure in the ram switches back to close the bolt...if you don't know what I'm talking about then don't bother with the upgrade...infact, sell your cocker to the nearest informed paintball player. So the point is that 35psi of cocking pressure will only chop if you are shooting quail eggs (and why would you shoot a poor birdy's eggs out of a paintball gun you sick person you).
It beats the hell out of the Shocktech "Phat" Hammer that I'm currently using. The only reason I don't have one is a huge shipping fiasco with professional paintball, which looking back on it, wasn't really anyones fault. So I give it a 9, because I don't have one yet.