U-Boat marked and Austrian Capture M91 Mosin - What is this thing?

MrClark, the red is a little synthetic grease I hadn’t wiped off the metal when I took the picture. However, the rifle has been bedded with brass shims that were nailed in the stock at the contacr points. Maybe the Finns did this?

Ridolpho, can you please paste the link to K.H. Wrobel’s post here?

Thanks

Jake: Here is the link.German Landsturm with Rifle Mosin.Nagant M/91

Ridolpho

I'd be very surprised if the U124 marking has anything to do with Untersee Boots. According to these guys it did a lot of nothing during W.W.I.
U 124 - German and Austrian U-boats of World War One - Kaiserliche Marine - uboat.net
Rummage around here.
Mosin Nagant Rifle Guide to Proofs and Markings

Thanks guys.

I've looked through all of those markings and I can't find it. Maybe someone else will chime in who has seen it before.