History of the Ammunition Industrial Base - JMC - U.S. Army

The computation of ammunition requirements was different from other classes of
supplies. It ranked high in importance and was sometimes compared to supplying food to the
troops. Ammunition was more complex because the rate of consumption was irregular.
Ammunition requirements were based on day of supply estimates, which was the average
number of rounds that would be expended by each type of weapon per day in the course of
planned operations. There were no tables showing the number of rounds to be issued to any
tactical unit. The rate for each weapon included a breakdown showing the estimate for each type
of shell, high explosive, armor piercing, incendiary, etc; and for each type of fuzes when more
than one type could be used on a shell. For training ammunition, specific quantities per man
were authorized. 90
As planners struggled with the best way to predict field requirements, they experimented
by linking equipment production schedules to projected ammunition requirements. For example,
bombs and ammunition for aircraft called for production of a five-month supply for each
bomber, based on aircraft production schedules, estimated number of sorties a month for each
plane and the number of bombs dropped and rounds fired per sortie. The computations soon
resulted in over production of bombs because all planes did not go immediately from factory to
overseas theater or they didn‟t engage in bombing runs. This resulted in production cuts for
bombs in 1943. Then, as air attacks escalated in 1944, many of the cuts had to be restored and
production was reinstated. 91
Adding to the fluctuation included the frequency of equipment changes that occurred
1940-1945. For example, the number of men in just one infantry regiment decreased over the
course of the war and its requirements for pistols, trucks and rifles all decreased before 1942 and
increased by 1945. The cumulative effect of these changes was enormous and nothing was
static.
At the beginning of WWII and two years into it, replacement factors for ammunition
were the result of guesswork. No one conclusively knew how long Army equipment would
withstand under combat conditions, nor did anyone have accurate notions of how much
ammunition an infantry regiment or field artillery battalion would need. Some historians have
declared that the day of supply figures used in 1940 and 1941 were defective. The calculations
were too high and didn‟t allow for differences among theaters. 92
The Ordnance Department came into WWII relying on Frankford Arsenal for small arms
ammunition, artillery projectiles, cartridge cases, optical and fire control instruments, gages and
pyrotechnics. Picatinny Arsenal focused on artillery ammo, explosions and propellants. While
the production capacity was never enough to meet the needs of wartime demand, each
manufactured specialized ordnance when expansion was needed. Between 1938 and 1941
Frankford‟s small caliber yearly capacity increased from 400 million rounds to 630 million
rounds by increasing shifts and expanding lines. 93
The small arms ammunition base is described to be built in waves throughout WWII.
Total capacity increased to over 41 billion rounds produced at 12 ammunition plants by 1945.
90 Ibid, 53.
91 Ibid, 51-52.
92 Thomson & Mayo, 47-50,
93 Ibid, 188.
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