Originally Posted by
PWC
Wish I were good enough to tell the difference to "need" 1/2" sights.
If you don't know what they are, you probably don't need them. The whole intricate workings are pretty cool.
Here's a better explanation:
A. The two aperture assemblies are identical except for the eyepieces which have different peep hole diameters. The aperture with the .0595 in. peep hole will be installed as standard with the .0520 diameter aperture available as an alternate.
The hooded eyepiece is designed to eliminate glare and reflections on the sight aperture, and to provide 1/2 minute changes in elevation. Each eyepiece is selectively fitted and matched with its individual aperture. You should not attempt to disassemble the aperture assembly or to change eyepieces on an aperture.
The peep hole is .002in. vertically eccentric with the other diameters of the eyepiece. Thus rotating the eyepiece 180 degrees clockwise or counter-clockwise raises and lowers the line of sight. Two spring-loaded balls in the eyepiece engage a vertical "v" notch in the face of the aperture to retain the eyepiece in each position. The position of the eyepiece is indicated by a notch at the rear face of the eyepiece.
Each click of the elevation knob gives a change of 1 minute. Rotating the eyepiece so that the indicator notch is at the top moves the point of impact of the bullet up 1/2 minute. With the indicator notch at the bottom, the point of impact of the bullet will be moved down 1/2 minute. In operation you would use the elevation knob to get just above or just below your desired point of impact, and then rotate the eyepiece up to get an additional 1/2 minute of elevation or down to lose a 1/2 minute.
B. The National Match sight base marked "NM/2A" is undercut to accept the hooded eyepiece. The 64 pitch thread of this sight base and of the National Match windage knob produce a 1/2 minute change in windage for each click of the knob. Thus the National Match Rear Sight is capable of 1/2 minute sight changes for both windage and elevation.
C. The National Match front sight has a blade width of .065 -.005, and is identified by the letters "NM" and the numbers "062" on its right side. The width of the sight blade of the standard M1 or M14 rifle is .084 -.010.
Last edited by dryheat; 07-06-2021 at 06:58.
If I should die before I wake...great,a little more sleep.