I have been lusting after a Merkel O/U since my Dad told me about them almost 50 years ago. One of his friends had "liberated" one during WWII and Dad was impressed. I have a couple of Merkel drillings, but need the classic solid rib, three-piece forearm O/U for clays, pheasant, ducks, geese and my ego. I've found a mid-30's beater, a 401E that's a cosmetic nightmare but mechanically solid. The wood is scraped, dinged and abused. The blueing is gone from the lever and the barrels are rusted and lightly to moderately pitted. The bores are bright and not pitted, the lever is centered and it locks up tight quietly.
I like the idea of answering "What's that thing?" with "Just an old Merkel."
Try as I might, Googling here and there, I can't find much info about the 401E. Can anyone point me to a reference or fill my head with facts and opinions? Thanks much