Most pleasing to have members from the other side of the Atlantic. I wonder how easy it is to find spares for older airguns over there. You might therefore find it helpful to know that there are at least two British firms that specialise in spares over here: Knibbs and Chambers. A Google search will produce their websites and offerings. In addition, the members here are excellent with regard to advice relating to everything there is to know about airguns.

Rgds
A