An Improved Battlesight Zero

for the M4 Carbine and M16A2 Rifle

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.  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.

1. Flip the rear sight back to the unmarked aperture. This will reveal a hole in the top of the handle.

2. Rotate the sight wheel all the way down. Will probably be exactly at 8/3 (6/3). Don't force it down.

3. Using a 1/16" Allen wrench loosen the screw (under the revealed hole) in the sight wheel 3 full turns. Leave the wrench in the screw.

4. Rotate the bottom half of the sight wheel two clicks clockwise. This will raise the sight body if you look at it while you're turning it.

5. Tighten the Allen screw, remove the wrench, and confirm the sight bottoms out at 2 clicks BELOW 8/3. If not repeat the procedure until it's right.

6. Battlesight the rifle per the -10 with the following exceptions:

1. Sight should be at 8/3 -2 clicks, that is, all the way down, not up a click.  Please note removable handle sights are marked 6/3 (rather than 8/3); also some are in ‘half-clicks’ as well. There should be 3 clicks between 3 and 4 on the knob. If there are 6 clicks then the sight needs to be set at –4 clicks (instead of –2).

2. Small aperture, nose to firing handle weld.

3. Distance is 50 yards.

4. Point of aim should be point of impact of bullet.

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.

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 (santose@compuserve.com).

Original document: 990104

Copyright 1999, 2000. All rights reserved.

Note To Users of Carbines with the A1 style rear sight: This 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 stype aperture (or the A.O. Same Plane sight), then use the small (long range) hole for zeroing.

U.S. Marine Corps 25-Meter Zeroing Procedures

(By following the steps below and establishing a zero at 25 meters, your M16A2 rifle sights will be set with a 300-Meter Battlesight.)

1. Do not move Front Sight post at this time. It was set at the factory or by a previous shooter and should be very close to your zero.

2. Center the Rear sight aperture by turning the windage knob left or right. (This is called Mechanical Zero Windage.)

3. The Unmarked aperture should be up.

4. Rotate elevation knob in the Down direction (counter-clockwise). The Elevation Knob should stop Three Clicks past the 300-Meter mark (NOTE: newer rifles may be set like this do not worry about it). The rear sight should be all the way down on the last whole 'Click' before it bottoms out. This is called Mechanical Zero Elevation for the rear sight. If your range scale will not line up in the above manner, an armorer will be required to adjust the range scale for you. (NOTE: Again this really is not required - some rifles bottom out on the 3/8 [or 3/6 for carry handles]. If you really want to adjust it then see the note at the end of these instructions.)

5. Now rotate the Elevation Knob "Up" once click past the 300-Meter mark. From this point on, the rear sight elevation knob should not be moved. Any changes in elevation required in the following zeroing steps are made to the Front Sight Post ONLY.

6. Carefully aim and fire at the center of the target bull's-eye. Take your time and be sure to use the sight picture illustrated (in the Operator's Manual).

7. If your shot group is not in the Center of the bulls-eye, use the squares on the target sheet to calculate the required "Clicks" necessary to move you next shot group (Squares are 3/8" x 3/8") into the bulls-eye. (Remember that any changes in elevation are made by moving the front sight post.) The squares are numbered around the edges of the target (see the Operators Manual for an illustration of the Target) to equal the number of clicks required to move the shot group to the bull's-eye.

Barrel Length    Change Per Click

       20"           3/8" for Elevation

       20"           1/8" for Windage

   14.5"/16"      1/2" for Elevation

   14.5"/16"      3/16" for Windage

8. In order to Raise your next shot group, rotate the front sight post clockwise. (one click will move the strike of the bullet one vertical square on the target sheet [20" rifle with A2 sights] - or consult the table in step 7).

    In order to Lower your next shot group, rotate the front sight post counter-clockwise (one click, as above, equals one square).

    Changes in windage are made with the windage knob. (Three clicks will move the strike of the bullet one horizontal square on the target sheet.)

    In order to move the shot group to the Left, turn the windage knob counter-clockwise.

    In order to move the shot group to the Right, turn the windage knob clockwise.

9. Carefully aim and fire another group at the center of the target bulls-eye.

10. Repeat steps 7 through 9, if required.

11. If your group is on target, your sight is now "Calibrated". To place your actual 300-Meter zero on the Rifle, you must rotate the elevation knob on click "Down". (The range scale's 300-Meter mark should now be aligned with the mark on the receiver.)

NOTE:  If your rifle bottoms out at 8/3 then follow these instructions to get the sight to bottom out at 8/3 –2 clicks.

1. Flip the rear sight back to the unmarked aperture. This will reveal a hole in the top of the handle.
2. Rotate the sight wheel all the way down. Will probably be exactly at 8/3 (6/3). Don’t force it down.
3. Using a 1/16" Allen wrench loosen the screw (under the revealed hole) in the sight wheel 3 full turns. Leave the wrench in the screw.
4. Rotate the bottom half of the sight wheel two clicks clockwise. This will raise the sight body if you look at it while you’re turning it.
5. Tighten the Allen screw, remove the wrench, and confirm the sight bottoms out at 2 clicks BELOW 8/3. If not repeat the procedure until it’s right.