NOTE: To initially establish your zero, first set the windage so that with windage index line on the rear sight base aligns with the center line of the windage guage on the receiver. This is mechanical zero.
(a) Iron sights (M1 rifle): The rear sight can be adjusted to correct for a wind that is strong enough to blow a bullet off its course, or simply to change the strike of the bullet to another spot on the target. The strike of the bullet can be made higher or lower (elevation) or can be moved to the right or to the left (windage). The elevation and windage knobs make audible clicks when they are turned, and each click changes the strike of the bullet approximately one inch on the target for every 100 yards of range. For example, 2 clicks of either elevation or windage will move the strike of the bullet approximately four inches on a target at a range of 200 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.
(b) Zero and Battle-Sight for M1: Every rifle has certain characteristics that make the individual piece fire a little high, a little low, a little to the right or the left. To be able to get consistent hits, the rear sight must be zeroed for the various ranges, and the sight setting recorded. The data for the rifle's zero is easily kept in the accessory compartment of the stock for ready 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. Several rounds should be fired from a bench or sandbag rest from various ranges to find and confirm the zero settings. The battle sight setting is the 300-yard zero, less two clicks. When two click are subtracted from the zero elevation, it causes the rifle to be zeroed in at the point of aim. In other words, the location of the shot group is moved from the center of the bull's eye to the lower edge. With this sight setting, a rifleman can hit his point of aim at 300 yards and can engage man-sized targets at ranges from 0-400 yards by aiming at the center of mass.
(I) To calibrate the rear sight to the battle sight setting you:
(II) To set the battle sight zero on the older type sight (with the locking nut) you:
|200 yards||100 yard zero -1 click|
|300 yards||200 yard +2 to 3 clicks|
|500 yards||300 yard zero +7 to 8 clicks|
The above information was copied from "The Fighting Garand Owner's Manual", Edited by Nolan Wilson - Chapter II, Description & Operation - Section 7.
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