Continuing my series on articles found at the Defense Technical Information Center (DTIC), today we will be taking a look at another landmark document in modern firearms history, An Effectiveness Study of The Infantry Rifle, by Donald L. Hall, and more commonly known as the Hall report. The significance of this work is difficult to overstate, as it was one of the first comprehensive examinations of lightweight, high velocity ammunition. It’s purpose is conveyed in the introduction:

In accordance with the request of Office, Chief of Ordnance in
their letter /00 474/18 (s) dated 28 Nov 50, a study has been made of
the effectiveness of an infantry rifle. This report was prepared without
regard to present established military characteristics of the Army
Field Forces, since the purpose of research is to provide basic data
which may assist Army Field Forces in developing future reqitirements.
The status of critical raw materials was not considered. The conclusions
contained herein are tentative and are subject to experimental
confirmation.
In evaluating such a weapon, it is necessary to consider its probability
of hitting when in the hands of a combat soldier, its ability to
wound, and the weight of rifle and ammunition. These characteristics
are somewhat dependent on each other. The probability of hitting of a
rifle is primarily dependent on the range and muzzle velocity, or more
explicitly on the flatness of the trajectory. The wounding power is a
function of mass, striking velocity, and bullet shape. Both the hit
probability and the wounding ability could be improved by increasing
the muzzle energy, but this would increase the weight of both the gun
and the ammunition thus decreasing the number of rounds that the soldier
could carry.
In this study a family of weapons was considered. The caliber was
varied from .30 to .21 and the weight of the charge was taken to be 1.0,
0.8, and 0.6 times the charge (53 grains) normally used in the present
standard Ball M-2 Cal. .30 ammunition.

Not all the premises of the Hall report proved true. For example, it was later determined that the probability of a hit of the rifle-shooter system was much more overwhelmingly influenced by the shooter, and not as much by the capabilities of his weapon as was previously thought. However, the Hall report represents the first baby steps of the small caliber high velocity ammunition concept towards its eventual adoption.