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XM723 Mechanized Infantry Combat Vehicle

As early as 1958, an Infantry School study sought to define the characteristics of an infantry fighting vehicle with substantial armament and protection that would allow the armored infantry squad to fight from the vehicle, although no action was taken on the study’s recommendations. In early 1964, the Department of the Army ordered a development effort for mechanized infantry combat vehicles (MICV), to include an interim vehicle, the MICV-65 (Mechanised Infantry Combat Vehicle-1965), and an objective vehicle, the MICV–70. The MICV specification demanded a vehicle capable of engaging in combat through organic weapons, as well as the weapons of the carried infantry team, while providing greater ballistic and NBC protection than the current M113 APC.

After rejecting the XM765 AIFV derived from the M113, the Army gave FMC a contract to develop a better armored and more mobile version. In April 1972, the Army issued an RFP for a new Mechanized Infantry Combat Vehicle [MICV]. Six companies responded, and three were selected (Chrysler Corporation, FMC Corporation, and Pacific Car and Foundry) to develop cost estimates and design prototypes. In November 1972, FMC was awarded a $29.3 million cost plus incentive fee (CPIF) contract for Engineering Development and Advanced Production Engineering. This contract covered the cost of the design, development and fabrication of three prototype vehicles, a ballistic vehicle, 12 pilot vehicles, and associated systems engineering, product assurance, and test support.

The MICV–70 project led to a purpose-built vehicle, the XM723 MICV, armed with light cannon and a machine gun in a one-man turret, and provided with vision devices and firing ports for the mechanized infantry squad it carried. The XM723 had a troubled development history due to difficulty in meeting performance requirements within the specified cost, weight, and dimensions, despite an optimistic outside contractor report that claimed the MICV–70 specification should have been both attainable and cost-effective.

The prototypes, called XM723, were completed by the summer 1975. The XM723 owed some design heritage to the US Marine Corps Amtrac series of vehicles, rather than the M113. The MICV could not be built to meet the required 35,000-pound to 38,000-pound weight band, resulting in the weight specification being changed to 43,000 pounds. The actual weight of the first ED vehicle was 43,700 pounds. These increases are attributed to cost tradeoffs (substitution of steel for titanium bars) and design changes required primarily to meet reliability and durability requirements in the mobility area.

Prototype to the Bradley Fighting Vehicle, the XM723 operated with a crew of 3 and carried 9 Infantrymen. The turret was armed with a 20mm cannon and 7.62mm coaxial machine gun. The design had a novel laminated steel / aluminium armor which was relatively light but gave improved protection against small arms fire up to 14.5mm.

In an effort to clarify this situation, in August 1968 Army Chief of Staff General William C. Westmoreland set up the Mechanized Infantry Combat Vehicle Ad Hoc Study Group (Casey Board), which was tasked to examine the MICV concept (but not the doctrine underlying it) and make recommendations to reduce the weight and cost of the vehicle. The board endorsed the MICV concept and made recommendations relaxing protection and endurance criteria, which yielded cost and weight savings of about one-third. Despite these concessions, the XM723 program struggled to meet its requirements.

The operational and fiscal conditions of the Vietnam War and its aftermath lowered the priority of the program, and even as the XM723 prototype was being delivered in December 1972, a variety of industry and field initiatives suggested that much of the MICV–70 requirement (especially as relaxed by the Casey Board) could be met through modifications of the M113, which had been pressed into combat missions in Vietnam. In addition, the combat record of the analogous Soviet BMP infantry combat vehicle with Arab forces in the 1973 war was markedly unsuccessful, casting doubt on the entire concept.

This situation was further complicated by the cancellation of the Army’s Armored Reconnaissance Scout Vehicle (ARSV) program in 1974; lacking resources for a new program in the wake of the Vietnam War, the service merged the Scout and MICV programs with the intention of producing mechanized infantry and armored cavalry variants of the XM723. The failure of the ARSV and its subsequent merger into the Mechanized Infantry Combat Vehicle program late in 1975 greatly increased the importance of the latter to the Army. It also introduced an entire new level of complexity into the XM723’s development.

Although the Scout and Infantry variants of the MICV were still automotively identical, they were envisioned as having different weapons stations. The infantry version was to continue with the one-man turret as planned—in fact, it was to receive two of them. The planned cannon armament was still in development; therefore, an interim weapons station mounting the M139 20-mm. cannon continued in development. The Scout vehicle was a different matter. Its reconnaissance mission placed a premium on observation for the commander. The original MICV arrangement, with the commander stationed in the hull behind the driver and beside the turret, was unacceptable. The Scout was thus to have a two-man turret, so the commander could be stationed at the highest point in the vehicle, with a 360-degree field of view. Also, in addition to the cannon and coaxial machine gun of the MICV, the Scout variant was to mount the tubelaunched, optically tracked, wire guided (TOW) heavy antitank missile, as a result of the Army’s post-Vietnam reorientation to European warfare, which foresaw a need for anti-armor firepower in forward areas.

Quite aside from the administrative and engineering complexity involved, this situation was insupportable. In a time of fiscal retrenchment and reductions in force, asking Congress for funding to produce a single vehicle with two hulls and three turrets seemed the quickest way to have the project join the MBT–70 and the ARSV. The embarrassment latent in this situation was all the greater given that the Army had dismissed the possibility of an M113-based MICV years before, due partially to the undesirability of a mixed fleet. To address these problems, in August 1976 the Department of the Army appointed Brig. Gen. Richard Larkin, assistant commander of the 4th Infantry Division (Mechanized), to head a task force to examine the MICV program. After three months’ deliberations, the Larkin task force recommended that development of both one-man weapons stations be abandoned. Instead, it was recommended that an essentially common vehicle with the same level of protection as the existing vehicle should be procured. This course of action was reinforced by the perception that the commander’s limited visibility and separation from vehicle’s weapons and sensors had been a major shortcoming of the BMP in 1973.

Combat experience was confirmed by experimental evidence. While the Larkin task force was sitting, human factors tests were carried out in the course of second-phase operational testing. These tests found that the XM723 MICV, which shared the BMP’s layout, was equally difficult to command, despite the addition of a light-emitting diode display to help the commander transmit target bearings to the gunner in the turret. Under the Larkin task force’s scheme, the cavalry vehicle would thus mainly differ from that of the infantry in carrying a smaller crew and more ammunition, while omitting the firing port weapons. In both roles, the vehicle was to mount the turret previously associated with the scout version. In some ways, this innovation was revolutionary. It put the TOW, which had previously been regarded as a company- and battalion-level antitank weapon operated by specialists, at the disposal of each mechanized infantry squad. It thus gave mechanized infantry units a remarkable density of antitank firepower.

In other ways, the addition of TOW was an evolutionary step. Mechanized infantry forces had, after all, traditionally deployed large numbers of antitank weapons, both to provide a positional anchor to support armored maneuver and to free up tanks that would otherwise be required for their protection in the defense. The proliferation of antitank missiles was thus analogous to deployment of the bazooka, which had been issued to each World War II armored infantry squad, rather than at the company level where it originally resided in other infantry tables of organization and equipment—or the machine gun, which went from being a battalion weapon to a squad weapon over the course of World War I, and from a squad to a fire team and even (as the assault rifle) a personal weapon during World War II.

Whether revolutionary or evolutionary, the addition of TOW to the Cavalry Fighting Vehicle at least had a firm basis in doctrine. In the summer of 1976, just before the Larkin task force began its deliberations, the Army Training and Doctrine Command (TRADOC) under General William DePuy issued a new edition of the Army’s key doctrinal manual, FM 100-5, Operations. This work marked a radical reorientation of the Army’s professional thinking from the problems of peripheral war and counterinsurgency in general, and Vietnam and its aftermath in particular, to those of central war in Europe against the forces of the Warsaw Pact. In particular, at the tactical level he envisioned a defensive screen of “covering forces,” well supplied with antitank weapons—armored cavalry units equipped with TOW-armed scout vehicles, for example. These units were to force the attacking formations to stop, deploy, and engage them, thus incurring delays and telegraphing plans. The time and intelligence thus gained would, in turn, allow the armored main battle forces to concentrate, while air and artillery firepower from the rear battle area would be brought to bear as well.

The TOW, then, was seen as an emerging doctrinal necessity for the scout variant. For its infantry counterpart, the addition of the missile was more important politically than doctrinally; a common hull and turret for the two vehicles made for a vital savings in development costs. Furthermore, without it, the MICV, whatever its virtues, represented only an incremental improvement over the M113 and its derivatives. The total cost increment for each vehicle equipped with TBAT–II as opposed to the basic XM723 design was given as $79,000 (Fiscal Year 1976) in congressional testimony. It is worth noting that much of this cost was for the thermal sight, an item deemed necessary in any event both for the scout mission and to match the night-fighting capability of the XM1 main battle tank.

For this relatively small monetary outlay, the XM2 gained the new guided missile capability that had made such an impact in the early phases of the Yom Kippur War without requiring the development of a new weapons system. Moreover, it did so by putting the weapons under armor, rendering them resistant to the suppressive fire used as a counter to antitank missile attacks in 1973. Previous mobile ground mountings for the TOW, on M151 jeeps and atop M113s, had been unprotected. As General Donn Starry, DePuy’s successor at TRADOC, stated: “We in TRADOC . . . decided to put the TOW on the MICV because we realized that if we did not put the TOW on the MICV, we would probably never have an MICV.” Even without this rather pragmatic rationale, the Army’s addition of TOW to the MICV made considerable sense in terms of the service’s available resources. Time and fiscal constraints left the Army with the twelve-man XM723 hull and automotive systems on its hands, with its development almost complete.

These were sized for a mechanized infantry squad the Army would likely be unable to field, within the constraints of the post-Vietnam volunteer Army. With only the gunner in the turret and the commander/squad leader in the hull, the XM723 was, in any case, configured in a manner both combat experience and experimentation suggested were at best inefficient and at worst untenable. Assuming the necessity for staying with the MICV hull and power train already developed, the TBAT–II design was a useful exercise, in effect taking up the excess volume in the MICV’s design while correcting the problematic configuration and addressing the perceived Soviet armor threat. A missile avoiding the mobility penalties inherent in the TOW would have been better and would certainly have made a more clear-cut argument for antitank capability for the new vehicles, but no such weapons system was available.

Preliminary work on the modifications necessary for the TBAT–II configuration having already begun, the redesign, based on the MICV Task Force’s detailed recommendations, went ahead quickly. Larkin’s group, cognizant of the increased level of complexity and expense this redesign entailed, recommended that the TOW installation be relatively simple, carrying two rounds rather than the four originally considered, in a nonelevating mount, unlike those being studied for specialized M113-based TOW carriers.

Similarly, they recognized the probability that the new turret would drive up the vehicle’s weight. In view of this problem, the Larkin task force recommended that the MICV’s amphibious capability be achieved by use of a water-barrier system. This was a bathtub-like canvas enclosure around the hull to increase waterborne displacement, as pioneered by the Sherman DD’s of World War II. Use of a water barrier was probably inevitable if amphibious capability was to be achieved, as the MICV’s hullborne flotation had become marginal at best.

Perhaps the most significant design impact of the new arrangement was on the squad. The original MICV was sized for the then-current elevenman infantry rifle squad standard throughout all types of infantry unit, whether mechanized, regular, airborne, or airmobile. Only six of these men, however, aside from the vehicle crew and squad leader, were placed where they could observe or fight from under armor. Accommodating the larger turret ring and providing stowage for reserve missile rounds effectively eliminated the odd two men.

Officially, a trend was emerging to reduce the size of the squad to nine men in view of manpower concerns; furthermore, Army research such as the Infantry Rifle Unit Study of the early 1970s had suggested that improved firepower allowed a squad as small as seven. At any rate, in practical terms, few Army infantry squads at this time were ever at full strength. Even under the relatively improved conditions of the early 1980s, many M113-equipped mechanized infantry platoons could field only eighteen to twenty-five men, making for de facto rifle “squads” of five to seven which concentrated on manning their most potent weapons first.

In 1975 the Armny had rejected two prototype designs for its Armored Reconnaissance Scout Vehicle and directed the project's staff to work with the prototype XM723 as the baseline cavalry vehicle. To consolidate the task forces, the Army combined both cavalry and infantry fighting vehicle requirements under the Mechanized Infantry Combat Vehicle prograi in August 1976. At the same time, under request by Congress, a task force was formed by the Army to evaluate the whole XM723 program to determine whether the vehicle would meetIthe future requirement of the Army. The Task Force recommended a new program called the Fighting Vehicle System consisting of two vehicles: the XM2 Infantry Fighting VehicleIand the XM3 Cavalry Fighting Vehicle.

The XM723 derivative was designated the XM2 for the IFV requirement and the XM3 for the Cavalry Fighting Vehicle requirement. FMC was quickly awarded a contract to produce the modified vehicles, and the redesign effort continued. In March 1977, the MICV program was renamed “Fighting Vehicle Systems” in recognition of its wider purview. Similarly, in May the departure from the original XM723 MICV concept was recognized by yet another redesignation: the MICV became the XM2 IFV, while the Cavalry vehicle became the XM3 Cavalry Fighting Vehicle (CFV). Based on recommended changes to the XM723, the M2 Bradley Fighting Vehicles was manufactured and fielded in the early 1980's.