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Zero an M16A1 Rifle 071-311-2004 Conditions: On a 25-meter range, given an M16A1 rifle, 18 rounds of 5.56-mm ammunition, a 250-meter zero target, and sandbags for support; one of the following situations exist: 1. You receive a rifle that you have never fired. 2. Your rifle is returned after repair. 3. You think something may have changed the battlesight zero. Standards: Battlesight zero the rifle so that five out of six rounds, in two consecutive shot groups, strike within the 4-centimeter circle on the target, using 18 rounds or less. Bullets that break the line of the 4- centimeter circle are accepted. Performance Steps 1. Determine if you must establish a mechanical zero for the rifle. The rifle must have a mechanical zero established if the rifle-- a. Is being returned to service after direct support (DS) or general support (GS) maintenance. b. Has not been zeroed for you. c. Has been dropped or otherwise damaged. 2. Select the long-range aperture "L" on the rear sight for zeroing (Figure 1). Figure 1. Long-range aperture "L" on the rear sight. NOTE: Once the zeroing is complete, flipping the sight to the unmarked aperture will cause the sights to be zeroed for 250 meters. Flipping the sight back to the "L" marked aperture will automatically extend the zero to 375 meters without additional adjustments to the front sight post. 3. Set the sights to the mechanical zero, if required. a. Set the front sight (consisting of a rotating post with a spring-loaded detent) (Figure 2). (1) Depress the detent using a pointed object such as a cartridge. (2) Rotate the post up or down so the notched disk is flush with the top of the front sight post well. Figure 2. Rear sight detent and front sight detent. (3) Rotate the post clockwise 11 clicks. b. Set the rear sight to the center. NOTE: The rear sight on the M16A1 consists of a rotating windage drum with a spring-loaded detent (Figure 2). 1 Performance Steps (1) Depress the detent. (2) Rotate the drum all the way to the left. (3) Rotate the drum 17 clicks to the right. NOTE: Each click changes the point of impact by 0.7 centimeter (17/64 inch) for every 25 meters of range. NOTE: The sight picture is obtained by aligning the rear sight and the front sight with the proper aiming point for your target. The sight picture depends on sight alignment and placement of the aiming point. 4. Establish the sight picture. a. Align the sights (Figure 3). Figure 3. Sight pictures. (1) Center the top of the front sight post in the center of the rear sight (A in Figure 3). (2) Draw an imaginary horizontal line through the center of the rear aperture so that the top of the front sight post touches the line (B in Figure 3). (3) Draw an imaginary vertical line through the center of the rear aperture that bisects the front sight post (C in Figure 3). (4) Verify the sight picture. NOTE: When you concentrate on the front sight post, the rear sight aperture will be blurred. b. Align the aiming point (Figure 4). 2 Performance Steps Figure 4. Standard zero target. (1) Position the top of the front sight post center mass of the scaled silhouette target. (2) Confirm that an imaginary vertical line drawn through the center of the front sight post splits the target. (3) Confirm that an imaginary horizontal line drawn through the top of the front sight post splits the target. 5. Fire a three-round shot group at the target. 6. Triangulate the shot group on the target. 7. Repeat steps 5 and 6 until the shot group falls within 4 centimeters. NOTE: The target is divided by labeled vertical and horizontal lines. It also has pictures of the front and rear sights with a direction arrow to assist you with adjusting the sights. 8. Adjust the sights to move the shot group within the zero circle, if required. NOTE: Do not adjust the sights if the shot group meets the task standard. a. Adjust the elevation. (1) Find the horizontal line (right to left) nearest the center of the shot group. (2) Follow the line either left or right to the nearest edge of the target. (3) Identify the number of clicks and the direction of adjustment shown at the edge of the target. (4) Adjust the front sight in the indicated direction by the appropriate number of clicks. (5) Record the adjustment made on the target. b. Adjust the windage. (1) Find the vertical line (up and down) nearest the center of the shot group. 3 Performance Steps (2) Follow the line either up or down to the nearest edge of the target. (3) Identify the number of clicks and the direction of adjustment shown at the edge of the target. (4) Adjust the rear sight in the indicated direction by the appropriate number of clicks. (5) Record the adjustment made on the target. 9. Fire a three-round shot group. 10. Repeat step 8 if the shot group is not within the 4-centimeter circle on the target. 11. Repeat steps 9 and 10 until the shot group is within the circle. 12. Compute the battlesight zero using table 1. Table 1. Computing the battlesight zero. 13. Label the rifle with the battlesight zero (Figure 5). Figure 5. Battlesight zero recorded on tape. a. Record the battlesight zero on the tape. b. Attach the tape to the rifle. Evaluation Preparation: SETUP: On a 25-meter firing range, the Soldier should have his or her assigned rifle and magazine. Give the soldier 18 rounds of 5.56-mm ball ammunition, and a sandbag for support. NOTE: You can train rifle marksmanship skills using any and all rifle marksmanship training devices (for example, Weaponeer, Basic Rifle Marksmanship, DVC 07-57). The live-fire evaluation of a Soldier's ability to zero a rifle requires firing on the standard zero range. The performance of this task for the Common Task Test (CTT) can be done in conjunction with live-fire on the standard zero range or during a unit weapon qualification firing cycle. BRIEF SOLDIER: Tell the Soldier to battlesight zero the rifle using no more than 18 rounds. Provide the Soldier with a scenario that requires him or her to establish a mechanical zero. Performance Measures GO NO-GO 1. Selected the long-range aperture "L." —— —— 2. Established the mechanical zero, if necessary. —— —— 4 Performance Measures GO NO-GO a. Set the front sight. (1) Rotated the post so the notched disk was flush with the front sight post well. (2) Rotated the post 11 clicks clockwise. b. Set the rear sight to the center by rotating the drum 17 clicks to the right from the extreme left point. 3. Fired a three-round shot group. —— —— 4. Triangulated the shot group. —— —— 5. Repeated performance measures 3 and 4 until the shot group fell within 4 —— —— centimeters. 6. Adjusted the sights to move the shot group to within the zero circle, if necessary. —— —— NOTE: Do not adjust the sights unless necessary. 7. Repeated performance measures 3 through 6 until five of six rounds, in two —— —— consecutive groups, were within the 4-centimeter circle on the target. 8. Used no more than 18 rounds total. —— —— 9. Recorded the battlesight zero. —— —— Evaluation Guidance: Score the Soldier GO if all performance measures are passed. If the rifle does not require adjustment, score performance measure 6 acceptable if the Soldier indicates that the sights are within acceptable parameters. Score the soldier NO-GO if any performance measure is failed. If the Soldier scores NO-GO, show the Soldier what was done wrong and how to do it correctly. References Required Related FM 3-22.9 TM 9-1005-249-10 5
"Zero an Rifle"