Escape From Stalag VIIIB
Telescopic Scope for M1 Garand
The M81 scope weighs 0.84 lb with Universal focus. Their maximum useful range was 800-1000 yds, with a magnification of 2.5 and a 35 ft field of vision at 100 yards. The M81 a cross-wire reticle, which is internally adjustable for windage and elevation in one minute of angle clicks.
The original rear sight of the M1 would not hold adjustments very well, so a locking bar was added in late 1942 which could be tightened after sights were set.
Each click of either elevation or windage changes the strike of the bullet approximately one inch on the target for every 100 yards of range, over its effective range.
One click will move the bullet strike:
1 inch at 100 yards
2 inches at 200 yards
6 inches at 300 yards
12 inches at 600 yards
Windage can be adjusted 16 clicks to the right or to the left of center index, and elevation can be adjusted from 0 to 72 clicks.
Remember, to be able to get consistent hits, the rear sight must be zeroed for the various ranges, and the sight setting recorded, and should be kept in the accessory compartment of the stock for reference. To move the mean point of impact up, raise the rear sight. To move the mean point of impact to the right, move the sight to the right, and so on.
The battle sight setting is the 300-yard zero, less two clicks.