This report examines how the U.S. Army’s mechanized infantry operations, tactics, and doctrine have dictated its requirement for an infantry fighting vehicle (IFV) that can carry at least nine dismountable soldiers. Since at least the Second World War (WWII), the U.S. Army has devoted substantial analytical effort to properly sizing and arming the infantry squad for optimal dismounted combat effectiveness, based on an ability to perform independent fire and maneuver tactics. The result of this analytic effort is a relatively consistent finding that the optimal squad size is nine to eleven soldiers. To support current infantry doctrine, the ability to...

The basic structure of the modern infantry squad began to emerge in 1946 and was formalized in Army doctrine in 1956. It remained essentially constant through several major conflicts, many important studies, and six formal changes in squad size and composition. In brief, that structure included squads made up of nine to eleven men (the preference being eleven), organized into two equally sized fire teams, aimed at optimizing the capability to independently carry out fire and maneuver tactics.

In this section, we review some of the key events and studies that led to the emergence, optimization, and retention of this...

Since the M3 halftrack was developed and fielded just prior to WWII, armored personnel carriers (e.g., the M75, M59, M113, and M1126³²), or APCs as they have come to be known, have been sized to carry a full-sized squad of nine or more soldiers, excluding the vehicle crew.

But at least since the late 1950s, the Army has also been examining concepts and developing prototypes for an IFV that could carry a full-sized squad. For example, the XM701 concept of the mid-1960s carried nine dismountable infantrymen and possessed a turreted 20mm cannon. The Army even evaluated and rejected a fielded...

Historically, the Bradley family of IFVs has performed well operationally. This is in part due to the fact that the Bradley was designed to fight and maneuver in support of tanks on a “mechanized army versus mechanized army” battlefield. Consequently, it performed well when subjected to the conditions for which it was designed. Operation DESERT STORM and Phase 1 of OIF provided proof of concept insofar as the BFV demonstrated that it could indeed be effectively employed in mounted fire and maneuver. It also performed well when used to support deliberate dismounted infantry operations. But in the later or COIN...