While we are guessing, I might as well go off the deep end too! Since there seems to be some variation (with and without the groove) within the same model type/year, could it be that each sight was individually registered to point of aim at 100 meters, so that some V-notches would be cut more or less deep than others to adjust the strike of the bullet? My 1906 does not have the groove. I also noticed, and it might be an illusion because of the camera angle, but it appears that the "web" of the sight where the notch is cut is varies in thickness, i.e. Luke's 1916 appears thicker than the 1917. My 1906 has the thick web. This could suggest that the Navy rear sight may have been produced by more than one source, with final assembly and regulation performed by DWM. How's that for a flight of fancy?! <img src="graemlins/c.gif" border="0" alt="[ouch]" />
