Very good to see you put this rifle up for viewing here old Pal,
I'm hoping you get some answers.
It's a lovely stub twist barrel, and well made rifle. I
I've not seen anything quite like this bracket. Bayonet lugs yes, but this is not one of those.
Unusually long, so a support makes sense.
Fingers crossed someone here will know something!
Are you still hammering woodies and crows?
Richard.