I labor under a lot of misapprehensions, but that is not one of them.

"Liner" translates as Futterlauf, Einlegerohr, and Seelenrohr according to Wrterbuch der Waffentechnik, Zusammengesetzt von Joachim Grtz. They all make sense to me in a Germanic sort of way. Give me an example of the antique gunmaking terms you are referring to.

I have another dictionary called Technisches Wrterbuch fr Waffenfreunde, Schtzen und Jger, Verlag J. Neumann-Neudamm, Melsungen, but it is much smaller and not nearly as good.