Sniper Tank!

Sniper Tank! by Captain Pete Mattes and Sergeant First Class (P) Frank Monroe Long-range engagements and the development of sniper tank crews have long been elusive goals of the armored force. Current tank gunnery doctrine (FM 17-12-1 wK3, Tank Combat Tables) recommends that engagements begin at 1500 to ZOO0 meters if the tactical situation permits. This recommendation is based on considerations of probability of hit (Ph), probability of kill (Pk), the effects of the dirty battlefield, and limited on-board ammunition. There may be situations, however, that require crews to engage targets at extended ranges of 3000 to 4OOO meters. This suggests a need for sniper tanks and the techniques to train them. In December 1990, the Weapons Department, U.S. A m y Armor School, set out to evaluate a variety of long-range gunnery methods and compare their effectiveness. The goal was to determine if one technique could provide a significant advantage over the others and be useful to commanders whose situation requires long-range engagements. This article provides an overview of this evaluation and describes two of the techniques: the re-engage method and half-target-form adjustment. ~Re-engage - The current U.S. Army doctrine of re-lasing to determine a new ballistic solution follow-wingman and adjusts the lay of the reticle by half of the target form, as necessary. Long Range Gunnery Evaluation The test of the techniques consisted of three parts. The first phase, shot at Ft. box, involved firing 105-mm training sabot ammunition (M724A1) at half-size T- 72 frontal targets at a range of 2500 meters. Its purpose was to serve as a "proof-of-principle" to establish the procedures for each technique and lay the groundwork fqr further testing. Because service ammunition was not fired, the results had no affect on our final recommendation. The primary test occurred at Drinkwater Valley Live-Fire Complex at the National Training Center, Ft. Irwin, Calif., during January 1991. This phase consisted of firing 105-mm service sabot (M392A2) at 2900-, 3400-, and 3900- meter targets (H-1, T-72 frontal). After firing more than 350 rounds, the different methods demonstrated varying success at each range band. The reengage technique was equal to or better than the others through 3400 meters, which validated our current doctrine of re-engaging at established planning ranges. However, beyond 3400 meters, the half-target-form adjustment produced considerably better results, achiev- e re-ing a miss. The gunner always relays center of visible mass. ing twice the hit rate as th engage method. .Half-Target-Form Method - In order to verify these . - . .

_ . - .

. . After a miss, the crew either uses its own sensing or receives one from a conclusions with 120-mm service ammunition, Yuma Proving Grounds, Ariz., hosted the final phase. There, crews fired M829A1 service sabot at 3000- and 4000-meter targets using the re-engage method and half-target-form adjustment. The outcome supported the NTC results: at longer ranges, the half-target-form adjustment method produced better results. The lessons learned during this evaluation can be useful to any unit that finds it necessary to conduct long-range gunnery. It is important to keep in mind that these techniques are primarily for stationary tanks firing at stationary targets. This is because the success of these engagements depends on the tank-to-target conditions (range and ammunition) remaining the same, as well as on accurate sensings. To engage moving targets at these ranges is not recommended due to small target size, large lead offsets, and range changes. Changes in range and lead will make it extremely difficult for the gunner to take up a consistent sight picture or make half-target-form adjustments. Further, a moving tank should never attempt these engagements. Training Sniper Crews Commanders should recognize that not every crew can be successful at long-range gunnery. Commanders should carefully select sniper crews based on the following factors: 0The tank and crew have demonstrated a high degree of ac- 38 ARMOR - March-April 7991

Adjusting Fire with the Half-Target-Form Method Initial Sight Picture ... ... Subsequent Sight Picture

3390 METERS

0 Round Fired

3390 METERS

0 Sensing "DOUBTFUL LEFT' Correction ... Right Half Form

3940 METERS

3940 METERS

0 Round Fired 0 Sensing "OVERLINE" Correction ... Drop Half Form curacy in shorter-range engagements. 0 The crew has a thorough understanding of the fire control system and its operation. 0The crew has the knowledge and discipline to perform meticulous prepare-to-fire checks and frequent, precise boresighting. 0 The tank must be prepared carefully in accordance with the Armament Accuracy Checks in Appendix A, Fh4 17-12-1 wlC3 (Appendix B, EM 17-12-3, w/C2) and the prepare-to-fire checks in the appropriate operator's manual:

M60A3 - TM 9-2350-253-10-1.

M1 - TM 9-2350-255-10-1.

MlAl - TM 9-2350-264-10-1. 0 Frequent and extremely precise boresighting is essential. Significant changes in ambient temperature, daylnight, and overcastlsunny conditions may require boresighting as often as every two to four hours (depending on the suddenness of the change) to maintain optimum boresight. Do not use the muzzle reference system (MRS); check boresight using a muzzle boresight device (MBD). Once the tanks are prepared and manned by qualified personnel, the crews must concentrate on three skills: sensing, sight-to-target relationship, and reticle lay. Sensings are critical to long-range gunnery but difficult to obtain for a lone firing tank. At the NTC test, even after two relatively wet days, crew accuracy in sensing at 3900 meters was very erratic. There will be few instances when tank crews will be able to sense their own rounds in the event of a miss due primarily to local obscuration and weather. However, when the round strikes a target, the crew will normally observe the "splash regardless of conditions or sight (daylight or thermal). A firing crew must concentrate on the target and make every effort to sense its own rounds. For those occasions when the crew cannot observe, a wingman or another designated tank must provide sensings. The firing tank and sensing tank should coordinate positions so that the firing tank's obscuration does not obstruct the sensing vehicle. ~ ARMOR - March-April 7997 39

Crewmen in the sensing tank must understand the firing tank's fire plan to ensure they are sensing the correct target. Once the sensing vehicle has identified the correct target, the sensing crew must have the discipline to look at that target without being influenced by other tracers or shots by other tanks within their field of view. The sensing tank must be able to give clear and accurate sensings. Heat shimmer and refraction will cause problems for both firing and sensing tanks. Tanks conducting long-range engagements should seek an elevated firing position to limit these effects. Usually, ten meters of elevation above the intervening terrain will negate the effects of refraction and help reduce the amount of heat shimmer. Laser range finder (LRF) return selection is also crucial. At extended ranges, either all or a large portion of the target will be inside the GPS one-mil aiming circle (See figure 1). At those ranges, LRF beam expansion will spill over the target, giving incorrect returns. If the line of sight of the firing vehicle is unobstructed, first return logic should be used. The Half-Form Adjustment . Technique Because the margin for error is so small, the gunner of the firing tank must meticulously take up a center mass sight picture before lasing to the target. Once he fires, the gunner must maintain his sight picture and attempt to sense, if possible, making a mental note of the strike of the round. If the round hits the target, the gunner must keep in mind that it may require more than one hit to achieve the desired effect on the target. In this case, the crew should fie again using the same sight picture. If the first round was sensed as a miss, and the gunner has laid on and ranged to the target correctly, he should apply a standard correction as follows: a. The gunner will make half-target-form adjustments based on the sensings received. These target-form adjustments may correct azimuth and elevation separately or together. (For example, a sensing of "OVER, LEFT" would result in a correction of down half form and right half form.)

e. Figure 1 shows sample sight pictures and half-target-form adjustments. This illustration looks through the GPS and depicts the actual target-to-reticle relationship at the ranges stated. While this method of engaging at extended ranges was successful, it still does not provide the hit probability of engaging at closer ranges. Commanders should carefully consider the situation before employing sniper tanks, but to have a few designated crews trained and prepared will provide the commander flexibility in mission accomplishment that he would not otherwise possess.

b. The half-target-form adjustment allows crews to make a standard adjustment regardless of the target type or range. This is why it is critical that the gunner understand sight-to-target relationship.

c. As discussed earlier, at extended ranges (3000 to

4OOO

meters) the entire target will often fit inside the one-mil aiming circle of the gunner's primary sight (GPS). The half-target-form. method will still leave the aiming dot on the edge of the target with the first adjustment, compared to the standard one-mil correction stated in current doctrine. At these ranges, a one-mil correction in azimuth or elevation will normally be excessive. By comparison, a half-target-form adjustment in elevation at 3500 meters applied to a T-72 frontal is about .32 mils.

d. If a subsequent round ic a target hit, and the target stil be engaged, the gunner ta same sight picture. If the miss, he continues to makc a1 half-form corrections in the appropriate direction. Captain Peter J. Mattes graduated from the U.S. Military Academy in 1986. He served as a platoon leader, XO, and S3 air with 2-70 Armor, 1st AD. A graduate of the Armor Officer' Basic and Advanced Courses, he is currently assigned to the Gunnery Training and Doctrine Branch, Weapons Department, U.S. Army Armor School. Sergeant First Class Frank

E. Monroe served with A-3- 64 as a TC in CAT '85 and as a platoon sergeant in CAT '87. He participated in M1 operational testing in 1981, and has attended M1 master gunner course and 'ly a in and Ions ...--a . . . ucpai LI I lL, u.u. Army Armor School. 40 ARMOR - March-April 7997