Dick Williams Gun Shop, Inc.
4985 Cole Road
Saginaw, MI 48601
989-777-1240
I got this lead from another posting on the "forum" involving some really hard to find parts for the Model 25. They have bought out an old shop in Ohio and have some stuff that I have not been able to locate anywhere!
Ask for Doug Williams (son of the owner), nice chap and was very helpful to me. I told him I would spread the word but I am not sure he realized what that meant...LOL!
Here is the deal, they don't have a listing but if you call him with your needs they will check it out and tell you if they have it or not.
He stated specifically that they had a "lot" of parts for the M12 & 121. I know they have some parts for the M25, and I acquired a bunch of hard to find parts for the M14. With respect to the latter, Doug did mention they had magazine tubes.
REMEMBER...........they don't have a published list but seem quite able to determine quickly if they have what you need. I make no promises about what they might "now" have but I got some good/rare stuff and was treated with great courtesy as was another member of this forum.