1. Current Army/Marine Corps battlesight zero and it's procedures are well described in TM9-1005-319-10, the M16/M4 operator's manual. A recent copy of this manual is available for download at the Manual Depot. Procedures in the manual will not be repeated here.
2. The current 300 meter battlesight zero is a function of the sights on the rifle and I personally find it shoots too high for the vast majority of combat targets, including the Army's qualification ranges. The procedure listed here takes better advantage of the flat trajectory of these rifles as well as the use of civilian ranges, which are seldom surveyed in meters.
3. When zeroed at 200 meters, a distance twice that of normal combat engagements, these rifles have a very flat trajectory that is less then 2" from line of sight at all intermediate distances; a distance that's smaller than the normal dispersion of arsenal or factory loaded ammunition. This tiny trajectory arc allows very precise shooting out to 250 meters where the bullet is only 2" below line of sight.
4. A 200 meter zero has the happy coincidence of an initial trajectory cross-over at 50 yards, a distance available on almost all civilian ranges including many indoor ranges. This makes it easy to achieve a 200 meter battlesight zero without recourse to surveying your own range. If 200 meters is available you can fine-tune the zero at the real distance. And should when you get the chance.
5. The lowest sight setting, however, on these sights is 300 meters so the sight needs to be modified to preserve the markings on the sight (despite the fact that no one ever sets a range on these in the real world other than a USMC range). The sight needs to be set to bottom out at 8/3 -2 clicks. This will be the new 200-meter setting.
6. Battlesight the rifle per the -10 with the following exceptions:
7. Remember you're adjusting the FRONT SIGHT for elevation, not the rear, and that each click is about 1/2" (actually a little more) at 50 yards. You won't get it closer than that. Don't frustrate yourself trying.
8. You're done. Leave the sight in this position for 99% of your shooting.
9. If you have to shoot targets you KNOW are 300 meters away or more, just click to the right number on the sight.
10. If you're patrolling, set the sight to 8/3 and snap the aperture forward to 0-2. This will provide the same trajectory as above but with a larger, easier to see thru rear sight. Use this setting if you also have the M68 mounted as it's quicker to transition to if the sight fails. [Editor's Note - there is some variance with the offset of the A2 aperture - they SHOULD be a 2 click difference - however some manufactures produce them with larger offsets. Setting the sight to 3 then flipping to 0-2 might now work for your AR. Check it at the range, you want the group to be centered at 50y, you might need to set the sight at 3 +2 or even 4 to get the large aperture to be correct]
11. If you have an M68 CCO (Aimpoint CompM-XD) optical sight battlesight it to 50/200 as well. You can shoot to 300 meters by merely holding "over a dot."
12. This battlesight zero is valid to 300 meters for both the M16A2 and M4 Carbines and their AR15 sisters. It's valid with any ammunition that approaches the specs for M193 (55gr) or M855 (62g) Ball ammunition. It works for both rifles and carbines due to the offsetting influence of higher muzzle velocity in the rifle being offset by the longer sight radius that moves bullet strike less per click. This is battlesight, not X-ring shooting!
13. This battlesight zero does not reflect the doctrine of the US Armed Forces, however, it reflects the personal use of these weapons in combat and in training for over 34 years.
14. Comments to: Lt. Colonel Chuck Santose (email@example.com).
Original document: 990104
Copyright 1999, 2000. All rights reserved.
Note To Users of Carbines with the A1 style rear sight or users of Flip-Up Sights: This 50 yard zero works really well. If you have the original sight aperture use the unmarked (short range) hole to zero the rifle. If you have upgraded, and use the A2 style aperture (or the A.O. Same Plane sight), then use the small (long range) hole for zeroing.
Thanks to Scott Thompson for sending this to us.