This production record to some extent was made possible by a leniency on the part of the Ordnance Department which we had not displayed before the war. When we could take plenty of time in ammunition manufacture our specifications for cartridges were extremely rigid. It soon became apparent that if we adhered to our earlier specifications we would limit the output of cartridges. It was found in a joint meeting of ordnance officers and ammunition manufacturers that certain increased tolerances could be permitted in our specifications without affecting the serviceability of the ammunition. Consequently new specifications for our war ammunition were drawn, enabling the plants to get into quantity production much more quickly than would have been possible if we had not relaxed our prewar attitude.
The ordinary service cartridge consists of a brass cartridge case, a primer, a propelling charge of smokeless powder, and a bullet made with a jacket or envelope of cupronickel inclosing a lead slug or core. Cupronickel is a hard alloy of copper and nickel. Steel would be the ideal covering for a bullet because of its cheapness and availability, but steel has not been used because it is liable to rust and to destroy the delicate rifling of the gun barrel. Cupronickel is a compromise, being strong enough to hold the interior lead from deforming, but not so hard as to wear down excessively the rifling in the gun barrel.
Even as we entered the war the long continued fighting in Europe had created a shortage in cupronickel, and by the time the armistice came it was apparent that this shortage would soon become so acute that we would have to find a substitute for cupronickel. This shortage had already occurred in Germany, where the enemy ordnance engineers had produced a bullet incased in steel which in turn was clothed with a slight covering of copper. The soft copper coating kept the steel from injuring the gun barrel. We ourselves were experimenting with copper-coated steel bullets when peace came, and would have been prepared to furnish a substitute had cupronickel failed us.
Some of the earliest ammunition sent to our forces in France developed a tendency to hang fire and to misfire; and a liberal quantity of it, amounting to six months' production of the Frankford Arsenal, was condemned and withdrawn from use. This matter was aired fully in the newspapers at the time it occurred. It developed that the faulty ammunition had been produced entirely in the Frankford Arsenal and that the cause of the trouble was the primer in the cartridge.
The primer in a cartridge performs the same function that the flint did on the old-fashioned squirrel guns—it touches off the explosive propellant charge. But whereas the flint sent only a spark into the powder, the modern primer produces a long, hot flame.
The primers in the ammunition manufactured at the Frankford Arsenal had given ordinarily satisfactory results in 12 years of peace-time use. The flame charge in this primer contained sulphur, potassium chlorate, and antimony sulphide. Produced under normal conditions, with plenty of time for drying, this primer was satisfactory. But sulphur when oxidized changes to an acid extremely corrosive to metal parts, and oxidized primers are liable not to function perfectly. Heat and moisture accelerate the change of sulphur to acid; and if there happens to be bromate in the potassium chlorate of the priming charge, the change is even more rapid.
An investigation of the Frankford Arsenal showed that these very elements were present. Because of the haste of production of cartridges, too much moisture had been allowed to get into the arsenal dry houses. The potassium chlorate was also found to contain appreciable quantities of bromate.
The condition was remedied by adopting another primer composition. And then, to play doubly safe, the Government specifications were amended to prevent the use of potassium chlorate containing more than 0.01 per cent of bromate.
However, this condemned ammunition was but a trifling fraction of the total output or even of the production then going on. The primers used by the various private manufacturers of ammunition functioned satisfactorily.
While we were not rigid in our specifications for the bulk of the service ammunition, in one respect we were most meticulous, and this was in respect to the ammunition used by the machine guns mounted on our airplanes. For these weapons we created an A-1 class of service .30-caliber cartridges, since it was highly important that there be no malfunctioning of ammunition in the air. Every cartridge of this class had to be specially gauged throughout its manufacture. This care resulted in a slower production of airplane cartridges than that of those for use on the ground, but we always had enough for our needs.