Milsurp After Hours

I was looking back through these photos and have a question. This one marked "volleysight"
has me stumped. Obviously the knob turns, but what does it do, I can't see where it moves anything
except the pointer on the dial.....

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Long range volley sights. The knob on the arm shouldn't really turn, it is supposed to be solid fixed to the arm. The knob is used when aiming volley fire. The knob acts as the front bead for sighting through the rear volley peep hole. Put top of bead onto POA.

Not very exact, but such was volley fire at a distant target. The introduction of the machine gun to the battle field took over the roll of volley fire to create a beaten zone, so the volley sight became redundant, dropped from production half way through the First World War.

https://www.youtube.com/watch?v=lUA0RouS5Dg

There you are Vern.

The thing I didn't get was the rear sight, the video explained that, thanks guys....

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