Since no takers on the choke tube or brass, I'll substitute a hardcover book in great shape titled "Grouse and Woodcock" Field and Techniques, Lore and Equipment. by Nick Sisley.

Last edited by Wyogal; 01/21/15.
http://tse2.mm.bing.net/th?q=Laughi...adlt=moderate&t=1&mw=247Formerly Bearmgc near Grasshopper Glacier WY