While the .30 caliber rifle and ammunition were still being developed, some American researchers were coming to different conclusions about the requirements for a military rifle. In 1950 the Ballistic Research Laboratory (BRL), an Army unit based at the Aberdeen Proving Grounds, was asked to investigate combat rifle effectiveness. The resulting report titled An Effectiveness Study of the Infantry Rifle was presented by its author, Donald Hall, in 1952. This was a theoretical study of the effectiveness of different calibres, which concluded that significant improvements in hit probability could be expected of a small-caliber, high velocity cartridge due to its flatter trajectory, and that there would also be benefits in a considerable reduction in ammunition weight.
In parallel with this study, the civilian Operational Research Office (ORO) of the U.S. Army’s General Staff examined what really happened in rifle combat. The resulting report on Project BALANCE by Norman Hitchman, the head of ORO’s Infantry Division, also emerged in 1952. Hitchman’s report was based on World War II combat records plus new data emerging from Korea. This showed that the average distance for aimed bullet hits was in the region of 75-100 yards with 80% of effective rifle and LMG fire being reported at ranges of less than 200 yards and 90% at less than 300 yards. Even worse for the Ordnance Department were tests of its .30 cal Lightweight Rifle prototypes which showed that the recoil was far too heavy, leading Hitchman to report that the cartridge was vastly overpowered and that automatic rifle fire was a waste of time and ammunition. This was five years before the selective-fire M14 in 7.62x51 caliber was officially adopted for US Army service.