Tuning Fx barrel in a daystate?

You will need to machine some kind of barrel inlet adapter to fit the barrel of one brand airgun to the breech of another. I did a simple tube affair to fit an FX liner to my Crosman Ratgun and the Bluegun both 2240 based with aftermarket breeches. The liner and adapter are held together with set screws rather than threads. They both shoot well and are quite accurate.