The M1D sniper rifle was developed at the end of World War II, but never saw service in that conflict. It did see extensive service in the Korean War and the early days of Vietnam. As issued by the Army, it consisted of a standard grade M1 Garand rifle with a telescope and flash hider.
A steel sleeve was fitted to the barrel with a tapped hole on the left side for attachment of the scope mount, and a short rear handguard was attached forward of the scope mounting sleeve. The scope is offset to the left of the receiver to allow clip loading.
These rifles shoot as well as any M1 shoots, and they were not accurized as issued, although they certainly could be. A rifle like the M1D would probably be considered more of a DMR today rather than an actual sniper rig. Many original M1Ds were sold as surplus by CMP in the 1990s.
The 2.2X M84 telescope has a 7/8″ steel tube with a sliding sun shade and rubber eye cup. Field of view at 100 yards is 27 feet. The elevation and windage turrets are protected by hinged steel covers and provide 1 moa clicks that you can feel but are not audible. The elevation turret provides 40 moa of adjustment in one complete turn.
The scale on the elevation turret is marked for 0 to 900 yards (“0″ to “9″) with intermediate hashmarks indicating 50 yard increments between the numbers. I would guess this range scale is calibrated for M2 ball, since match-grade ammo wasn’t available when this scope was developed.
Zeroing these scopes is fairly simple, but you may need to fabricate a tool to adjust the elevation turret. When the turret is turned all the way clockwise, it stops on “0″. Set the rifle on “1″ and fire a group at 100 yards.
If the rifle is shooting low, add some elevation with the turret and disregard the range markings for now. Once the rifle is zeroed, we want to move the scale back to the 100 yard setting.
Look at the elevation turret and note the two round nuts in the center. The small center nut retains the elevation knob to the shaft. The larger outer nut locks the knob down and must be loosened to adjust the position of the scale.
You will need a tool to loosen the nut. I modified a screwdriver bit (see pictures). Loosen the outer nut, lift the elevation knob and turn it to the desired setting. If you loosen the nut enough the zero will not be disturbed. Once the scale is set where you want it, tighten the nut.
If the rifle shoots high and you need more down adjustment, loosen the large nut slightly so the turret clears the zero stop and turn the knob counter-clockwise past the stop. Tighten the nut. You will have to re-zero the scale as described above once you are happy with the zero. I used a collimator (boresighter) to keep track of my adjustments.