I am still 100% certain that this was a RE modified weapon. The fact that the picture is taken in the Hill 60 museum where mining was at its peak would back this up. Sappers cut them down because they were not issued with revolvers. Trying to swing a clumbersome rifle around and digging in such a tight space would be very difficult. Just getting one round off would be better than none and may just give you the upper hand when fighting in close quarters. Also you would not need to worry about aiming just point and shoot. In such closed spaces with little distance I would say you have more than a good chance of hitting something.