THe model dosnt matter they are all the same internally so its up to you. Really they aren't air efficent AT ALL unless you get a new valve thats high flow and in some cases you have to lower the pressure below 500PSI and the lower you go the less efficent it is. Hpwever a New Designs High Pressure Valve would be nice and they are like 30$. Add that to any spyder and its more efficent. Also by polishing the internals and by removing the Venturi efficency is also increased.
Yep I read through that site including the very handy Low Pressure FAQ. He has done something similar to what I want to do, but he says he gets 10 shots at 250 fps.... Ive read other people doing the conversion and getting about 25 at 270 fps... Id want at least 20 shots at 270+ fps. Id think a new valve, bolt, and polishing will help some and a very short freak back so no air is wasted brushing past the ball.
Wouldn't an old Spyder original or compact be less efficient than a newer Rodeo or something>?
I doubt it. The older spyders have heavier strikers so that mights effect the dwell somehow but other then that I dont know? So perhaps a newer one with a slim striker since they are lighter. A new valve is a must. I would reccomend a spyder Xtra. A rodeo would be a better once since it has a gauge you can tell the pressure and all. One thing you need to do though is make sure that there is as little of space between your new ASA and the valve. So you probably have to take the low pressure chamber out since that will only screw u up more. Second thought maybe a spyder victor would be the best. It dosn't have a VA so the gas wont take up as much volume. YOu have probably done more research then me but just from what I know here is what I would get.
ND HP valve
Madman Spring kit
Removed venturi from the bolt