I just noticed a nice improvement in russian reflector gunsight (presumably a PBP-1; see
http://gunsight.jp/b/english/data/sight-e-s.htm), that now looks as follows:

while previously I recall was like this:

that looked like drawn by a
moujik in his
izba.
HSFX has only for I-16 a furtherly improved one that don't know if more historically accurate:

GB
_________________________
Ardisco, colpisco, meninfischio ("I dare, hit and do not care about it!" - Written on a SM 79 "Sparviero" during Spain civil war)