Hi just got this today thinks it a German cannon optic think. Most of the finish-gone seams to be a black one. In an area where the finish is gone there are some faint markings that can be made out with magnifying glass.
M8 / 12 Z
15 Rachml (b or 5) Skala<O</O
1<SUP>st</SUP> 2 #s partially covered by paint and (might me one in front of 5 and on the end after one paint)
Note very hard to make out letters especially between r and n and ls so it might be wrong.
Word Rohr (tube) very clear and Skala (Scale)
That why think it German Black finish may be German or NDH they used German AT guns
What do you think and what is it and what is it worth?