I have a Czech euphonium from the 1920s. Its mouthpiece receiver is slightly smaller than the standard small shank trombone/baritone receiver. Small shank mouthpieces only go in about 1/2".

From what I can gather, the proper vintage piece for this instrument will also be about half an inch shorter than the normal small shank piece.

If anyone happens to have such a thing rattling around in a drawer somewhere (it'd probably insert into a small shank receiver almost for the entire length of the taper and might even be loose), and is willing to part with it, please let me know.

Cup shape is not important to me. Cone or cup is fine. I'm just trying to find out whether a properly-fitting mouthpiece will bring the pitch up the little bit it needs to go.

Please let me know if you have one of these that you don't need.