A red or yellow ram probably refers to the NForcer Gas Rams.The yellow you don't really want! To much power!The Red seemed to work OK in the Hatsan rifles.
Mini-Forcer comes in a 19mm check to see if that can be used.Now they can be charged or pressure reduced. I've done a couple with just Air and not Nitrogen.
OK.I think I got it...Once and for all.............3.25"Stroke length from "home" to sear engagement is.....3.25" measured with a digital caliper.The sear has a slot to permit about .100" movement prior to latching, and gives that back once the piston nudges forward.It still floors me that the ram is capable of a 5.375" That is 60% of max travel, and achieves a lower force than what is available.........So, armed with this information, can I adapt a Crosman NP or NP2 ram with a 4" stroke?Or will using 81% of stroke length be too much force??
A custom end plug could be made from steel or aluminum, but I don't think that is necessary. I have magnum Hatsans with the giant 840142-44 spring or equivalent air spring and they safely use plastic end plugs with recessed steel nuts for holding the stock to the action.Something like attached sketch (sorry, CAD needs upgrading) could be easily made on a small lathe or even a drill press.FWIW I think that rifle will shoot just fine with a coil spring and you will never have to worry about finding unicorn expensive and potentially leaky gas springs ever again.edit... OR you could also just modify the old end plug by chopping off the shoulder section ;-)