Introduction to the Stryker Mobile Gun System

(Published in Infantry, March-April 2006) The Stryker mobile gun system’s (MGS) mission is to provide direct supporting fires to infantry squads during the assault. Its primary function is to destroy or suppress hardened enemy bunkers and machine gun and sniper positions, and create infantry breach points in urban, restricted, and open rolling terrain. Additionally, in the self-defense mode, the MGS provides limited antiarmor capabilities. Overview The MGS is a direct fire supporting weapons system that has a 105mm cannon turret mounted on a Stryker chassis. It has a crew of three, which includes the driver, gunner, and vehicle commander. The MGS provides the infantry commander the rapid-fire precision capability of a high-caliber round — a personal sledgehammer. Each infantry company has one MGS pla toon, which is made up of three MGS vehicles and crews. This equates to nine MGS per Stryker battalion and 27 in the Stryker brigade combat team (SBCT). The MGS has the capability of firing four different types of service ammunition: the high-explosive, anti-tank (HEAT), high-explosive plastic tracer (HEP-T), sabot, and canister. Each round provides the commander a unique capability. The MGS carries 18 rounds and uses an automatic loader. The mission equipment package has eight rounds in a ready configuration in its carousel and an additional 10 rounds in a replenisher for reloading the carousel. The MGS is controlled through a fire control system computer, which tracks round locations in the carousel and replenisher and has ballistic solutions for each type of round. The MGS also has a coaxial-mounted M240C 7.62mm machine gun and a pedestal-mounted M2.50-caliber for the vehicle commander. The weapons platform is stabilized and can fire 360 degrees while moving. The MGS platoon consists of three mobile gun systems with crew and can be fought as an organic platoon, such as one MGS in support of an infantry platoon, or some variation thereof. The MGS meets all the requirements of the Stryker fleet for mobility, survivability, and commonality of chassis repair parts. However, the MGS cannot perform vehicle self-recovery since it carries no internal winch system. It is survivable against 14.5mm armor-piercing rounds and travels at speeds up to 60 mph. Planning Considerations The MGS has several unique characteristics, including safety, security, and command and control considerations while integrated with mounted and dismounted elements, which must be considered when employing it tactically. Safety. MGS safety considerations significantly exceed the general considerations of vehicle movement with troops. Dismounted soldiers working in proximity to the MGS must be aware of its gun barrel blast area, critical hearing damage area, and back-blast area from target impact. Firing the MGS in an urban environment has the implications of overpressure from its firing blast, as well as its back blast, which will effect windows, exposed personnel, and loose debris. The following protective measures must be considered when firing the MGS:

• The immediate areas behind the gun muzzle, for a distance of 25 meters, require hearing protection to avoid eardrum rupture. — 37

• As hearing protective measures, all soldiers within the 25-meter range must be forewarned prior to firing the weapons system.

• Any vehicle within close proximity to MGS during firing must be completely buttoned-up to protect the hearing of its occupants.

• The back blast from point of impact throws incapacitating projectiles out to 100 meters.

• The cartridge from the fired round is ejected in an area of five meters behind the gun tube and causes injury on contact. Risk factors associated with each of these areas can be reduced through training and education. The most beneficial training method is to mark off the safety distances from the MGS to point of impact. Soldiers should observe and understand what the distances look like on the ground. Leaders should specify identifiable locations on the ground for limits of advance prior to using the main gun. To further complicate safety considerations, building structures must be carefully considered to avoid overmatching your target, which could completely demolish a building’s structure, penetrate buildings behind the target, and damage the structural integrity of a building, thereby denying or limiting friendly soldier access to the target building. Although the effects of each type of round has not been characterized on every type of building, an effort is underway to provide that data to field units in the future. The MGS also has a significant range safety danger zone associated with its arsenal of rounds. Leaders must take those ranges into account prior to employment. For example, a gunner may chose to engage a sniper location in a building with a sabot round. However, after that round impacts the sniper’s location, it has the potential to continue down range for up to 9km. This impact requires leaders to assess the down-range impact, which could be a town or friendly forces in that general direction. SBCT leaders need to ensure that whenever possible, they integrate full graphic control measures in to their operational plans, to include no-fire areas (NFA), fire coordination lines (FCL), and no-maneuver areas between the MGS’ planned firing positions and their targets, keeping all friendly forces well clear of the MGS’ muzzle-to-target line. Security. Local security capabilities for the MGS are limited. Its three-man crew has limited capability to observe areas of immediate proximity to the vehicle while mounted, and the crew cannot operate effectively with a crewmember dismounted. The SBCT infantry company commander must plan for providing security for these valuable assets. When operating in an urban environment, the deadspace must be observed by dismounted soldiers. These specific points must be considered during the planning phase:

• When mounted, the MGS driver can observe a standing person to the driver’s side at 32 inches and beyond, but he cannot see the ground immediately in front of the vehicle.

• On his side of the vehicle, the vehicle commander has a blind spot of several meters.

• Rear security must always be considered for the MGS; as with all vehicles, the rear is its most vulnerable area. These security issues also apply to the personal safety issues of the infantryman operating in close proximity to the MGS. Command and Control. The MGS’s primary role is to support assaulting infantry; as such, the MGS will frequently be attached in support of an infantry platoon. It operates on the FM frequency of its supported unit and takes fire commands from the maneuver commander, the company commander, and on down to the fire team leader, if the vehicle is assigned to support. The maneuver leader will ensure his forces are prepared prior to ordering the MGS to fire. The maneuver force will also coordinate movement in formations and coordination of fires. A vehicle intercom system handset, located on the rear of the hull, allows dismounted leaders to directly communicate with the crew to enhance coordination between dismounted infantry and the supporting MGS. Research and Developments During August 2005, a tactics, techniques, and procedures (TTP) development exercise was conducted at Fort Benning, Georgia. Observations from the exercise resulted in the development of several new operating methods, which are outlined below. Breach operations sequence of events:

• MGS moves into an overwatch position (200 to 500 meters).

• Assault element moves into position (mounted or dismounted) and provides flank security.

• Assault element provides observation on breach site. If dismounted, no closer than 100 meters.

• MGS notifies assault element “gun ready,” when it is oriented on the target and HEP-T round is loaded.

• Prior to assault leader giving fire command, leaders must ensure all soldiers are in covered positions with some level Figure 1. MGS Back Blast Area Overlay 38 — of hearing protection at time of firing.

• Assault element observes impact and determines if additional rounds are required to form breach. The current requirement for the MGS is to make a breach site in a double reinforced concrete wall within 3 to 5 rounds. The amount of debris and dust caused by the round exploding will take approximately 10 seconds to dissipate.

• Assault leader orders MGS crew to shift fires prior to conducting the assault. If mounted, the infantry carrier vehicle (ICV) quickly reaches the breach site; the crew dismounts and enters breach. The ICV then moves beyond the objective to provide far-side security. If it is a dismounted assault, the ICV provides suppressing fires as needed and, at the assault leader’s command, moves to the far side for security.

• The MGS should have an additional sector of fire for the coaxial machine gun because main gun rounds should not be fired when soldiers are in the gun line.

• Prior to the assault, a planning consideration is to conduct breaches sequentially or simultaneously with more than one MGS in support, if a secondary breach site is required for another building.

• Leaders should develop blast-area over lays, as shown in Figure 1, for operations planning to ensure unit safety. Destroying a bunker: In this scenario, the plan calls for the MGS to fire two rounds to destroy a standard NATO-constructed bunker. The first round, a high-explosive anti-tank tracer (HEAT-T) round, is aimed at the base of the bunker. It will destroy the major fortifications and its jet stream will incapacitate enemy personnel. The second round, HEP-T, is fired into the hole created by the initial round to destroy the bunker. Bunker engagements can be deliberately planned or occur hastily. In a deliberate attack, the MGS should maximize the use of its sights and prepare to engage the bunker from 300 to 500 meters. Following the engagement, it will provide overwatch for maneuver elements based on mission requirements. If the engagement is hasty, the leader of the maneuver element will order the MGS forward to destroy the bunker based on initial contact and spot reports. The MGS will destroy the bunker per procedure and provide overwatch while an infantry squad clears what remains of the bunker. Military operations on urbanized terrain (MOUT) operations: The MGS can operate in a MOUT environment as a complement to dismounted infantry by providing precision fires with its coax machine gun while the infantry provide local security and clear road intersections to protect the MGS flank. Per doctrine, HEP-T rounds are battle carried in a MOUT environment. A single HEP- T round will subdue any enemy personnel in a building should the infantry come across an overwhelming position. The MGS also brings the capability to address snipers in multi-story buildings. The coax machine gun has the capability to place precision fires; the main gun can fire a HEP-T round into a window or through an opening below the floor, destroying the enemy position from beneath. This same procedure can be employed to clear a roof top. An MGS can engage third- and fourth-floor windows from an impressive distance. There are multiple ways to communicate with an MGS crew in a MOUT environment. Although FM communications is primary, the driver can monitor the movement as well as the hand and arm signals of the dismounted elements ahead. There is also a telephone box mounted on the MGS for direct intercom communications with the crew. An experienced leader should stay with the MGS in a trail position to maintain maximum control of the dismounted infantry and MGS team. A rear security element is also necessary. Because coordination between mounted and dismounted forces is difficult, the dismounted infantry, without any means of communicating with the MGS crew, should stay clear of the MGS due to its limited field of view. Planning for MOUT movement requires evaluating routes due to the vehicle turning radius and main gun rotation. General observations and planning factors:

• FM communications should always be the primary form of communications with the MGS.

• Firing the MGS main gun/coax around a corner exposes 50 percent of the vehicle. Given a choice, the driver should pull forward to fire, exposing the most survivable section of the vehicle.

• Firing the vehicle commander’s.50- caliber exposes approximately 60 percent of the vehicle. — 39 “The MGS has several unique characteristics, including safety, security, and command and control considerations while in tegrated with mounted and dismounted elements, which must be considered when employing it tactically.”

MGS Breach Aiming Point Distance 1st Hole 2d Hole 3d Hole 200 Meters 2 mils from edge of wall.5 mil from top of first hole 2 mils left or right from center line of first hole Figure 3

• Street width can greatly effect the operation of the MGS main gun. To traverse the turret 360 degrees, the MGS requires a minimum of eight meters street width. MGS ammunition: The commander designates the ammunition mixture for the MGS based on mission, enemy, terrain, troops, time available, and civilians (METT-TC) considerations. The preferred main gun rounds in urban operations are HEAT-T, HEP-T, and canister. The HEAT-T round is used primarily against lightly armored vehicles (secondary armor), field fortifications, and personnel. The HEP-T round is used against field fortifications, bunkers, buildings, and crew-served weapons emplacements, as well as troops where blast, concussion, and fragmentation are desired with secondary armor-defeating capabilities. It is the primary round for creating infantry breach points. The canister round is primarily used in an antipersonnel role against troops in the open with the effectiveness to defeat an enemy squad from 100 to 300 meters. The sabot round is used as the primary armor-defeating round against tanks and tank-like targets. The sabot petals endanger accompanying infantry elements. They create a hazard area 70 meters on each side of the gun target line. The round can destroy an armored threat that wire-guided missiles cannot reach due to guidance wire obstacles along the missile’s flight path. Training Suggestions Breach point aiming. The current TTP for creating a breach point in a building requires the MGS to fire three to five rounds in pattern based on distances and offsets between rounds. For developing this skill, the crew should practice moving the aim point. The crew will need three or more circle-shaped cardboard cut-outs or other durable material 30 inches in diameter with across-hair drawn center circle, as shown in Figure 2. This exercise requires the gunner and an assistant at the building’s location. The gunner will take aim on the building and direct the assistant to place one of the circles on the wall centered on the gun sight reticle. The gunner will then move the aim point based on the offset and the assistant will again position a circle centered on the reticle. After three aim points have been attached to the building, proper positioning of the shot group should be evaluated. The intent is to practice making breach points from various distances and validate proper aiming offsets. Offsets will differ based on gun distances from the breach site, see Figure 3. Gun crews should develop their own matrices for breach offset points for various distances to improve engagement speed. MGS crews should use thermal sights to scan the targeted breaching wall to identify weak points in the structure, adjoining interior walls, and load-bearing walls, which will help the gunner place his round to create the effect that the maneuver commander intended. Coordination between gunner, driver, and vehicle commander. While maneuvering in a MOUT environment, gunners and drivers need to efficiently work together. A critical skill is the rapid engagement of a target after moving from a cover and concealed position. An MGS will be 50 percent exposed while firing in a flank direction. The gunner must position the gun tube in the direction of the enemy while the driver pulls the vehicle forward. Additionally, the driver should try to turn slightly in the direction of the enemy for increased survivability. Following gun firing, retrograde to the covered position must be practiced as the two events will happen very quickly; hopefully, without damaging the vehicle’s gun tube by ramming it against any covering structures. Movement with infantry. Habitual support relationships between MGS crews and specific SBCT rifle platoons should be formed to develop coordination and teamwork. During collective training at the infantry platoon level, it is important that the MGS be incorporated into the training plan, specifically for breach operations, MOUT training, and movement techniques. MGS Way Ahead The MGS will be fielded this summer to the 2d Cavalry Regiment (SBCT), Fort Lewis, Washington. The unit will also participate in the initial operational test and evaluation (IOTE) scheduled for February/March 2007. This weapons system will also be fielded to the 2d Brigade, 25th Infantry (SBCT), Hawaii. The full-rate production decision is scheduled to be made in late July 2007, following the

IOTE.

Additional information on the MGS can be attained through the SBCT Transformation Portal at www.sbct.army.mil/. Major Jonathan B. Slater is the assistant Training and Doctrine (TRADOC) System Manager-Stryker/Bradley, Fort Benning, Georgia. He received a B. A. from Johnson and Wales University and an M. B. A. from Long Island University. He has served in various command and staff positions including S3, 54th Troop Command, New Hampshire (NH) Army National Guard; deputy G1, NH National Guard; commander, Company C, 3-172 Infantry (Mountain); and rifle and anti-armor platoon leader, and HHC executive officer, 3-27 Infantry, 7th ID. Figure 2 40 —