I don't see a windage adjustment on that sight, so would that mean that the fine adjustment was to elevation only?
Or is that sight missing the adjustment knob at the pivot. There seems to be a threaded stem sticking out to the right side of the base.
I checked the BAR sights and the ones pictured adjust at the pivot rather than a adjustable slide.
A major complaint against the M1917 was lack of windage adjustment except by drifting the front sight.
Hesketh Pritchard gives a description of the apeture sighted P-14 as a sniper rifle, so despite lack of a scope mount it would still be a sniper rifle, though these days it would fill the role of designated marksman or sharpshooter.