Maj. Moulton first dealt with the inaccuracy of our 6-inch shell. He discovered the cause in the rotating band. Although but a slight portion of this band was upraised above the surface of the shell's circumference, yet the enormous force exerted upon the projectile to start it from the gun actually caused the cold copper to "flow" backward. The result was that when the shell emerged from the muzzle of the gun it bore around its sides an entirely unsuspected and undesirable flange. This flange not only shortened the range of the shell by offering resistance to the air, but it was seldom uniform all the way around, a condition giving rise to the idiosyncracies of our 6-inch shell as they were fired at the target.
The remedy for this was a redesigned rotating band, making it somewhat thicker in front. The "flow" of the copper could thus be accommodated without causing any detrimental distortion to the projectile. When this improvement was made the 6-inch shell became as accurate as any.
But Maj. Moulton was to make an even greater contribution to the 6-inch shell. This shell, like those of our other types, was square ended at the base. Maj. Moulton in his new design tapered in the sides somewhat, making the shell "boat ended." He elongated the nose, bringing it out to a much sharper point. The result was the first American "streamline" design for a shell. Shell of this new model were built experimentally and tested. The 6-inch gun could fire its old shell 17,000 yards, while the streamline shell went 4,000 or 5,000 yards farther—2 or 3 miles added to the range of an already powerful weapon by the application of brains and mathematics.
| MUZZLE VELOCITY. | ||
|---|---|---|
| Type. | Date. | Feet per second. |
| Early rifled guns | 1863-1870 | ██████████████████████ 1090 |
| Later rifled guns | 1870-1893 | ██████████████████████████████ 1466 |
| Early quick firers | About 1900 | ██████████████████████████████████ 1696 |
| Modern quick firers | 1914-1918 | ████████████████████████████████████ 1770 |
| RANGE WITH SHRAPNEL. | ||
| Smooth bores | 1815-1850 | ████ 1257 |
| Early rifled guns | 1863-1870 | ██████ 2004 |
| Later rifled guns | 1870-1893 | ████████████ 4120 |
| Early quick firers | About 1900 | ██████████████████ 6160 |
| Modern quick firers | 1914-1918 | ███████████████████ 6500 |
| RANGE WITH SHELL. | ||
| Smooth bores | 1815-1850 | █████ 1670 |
| Early rifled guns | 1863-1870 | ████████████ 3965 |
| Later rifled guns | 1870-1893 | ██████████████████ 6168 |
| Early quick firers | About 1900 | ██████████████████████ 7340 |
| Modern quick firers | 1914-1918 | █████████████████████████ 8500 |
| With streamline shell | 1918-19 | ████████████████████████████████████ 12130 |
The limiting factor in the development of light field guns has always been the continuous hauling power of 6 horses, which is about 4,000 pounds. The gun has been as powerful as possible within the limits of this weight, which includes the carriage and limber as well as the cannon itself. Improved technique and materials have reduced the necessary weight of the cannon from 1,650 pounds in 1815 to about 800 pounds to-day, permitting the use of weight for recoil mechanism and shield of armor plate without exceeding the limit.
The 800-pound nickel-steel gun of 1918 fires as heavy a projectile (12-15 pounds) as the 1,650-pound bronze gun of the Napoleonic wars. The improved material permits a more powerful propellant charge, which results in greater muzzle velocity, a flatter trajectory, and longer maximum range. The latter is due in part also to improved shapes of projectiles and the introduction of rifling. The efficiency of artillery is further increased by the introduction of high-explosive bursting charge. The modern 75-millimeter shell contains about 1.76 pounds of high explosive as against about 0.5 pound of black powder in shell prior to 1893.
The French were experimenting with streamline shell. We adopted the French streamline 75-millimeter shell and put it into production, calling it our Mark IV shell. Our regular 75-millimeter shell, known as the Mark I 1900 shell, had a maximum range of 9,000 yards. The Mark IV shell proved to have a maximum range of 12,130 yards, giving an increase in range of well over a mile. America up to April 3, 1919, turned out about 524,000 of these streamline shell.
The French also built shell of semisteel, steel to which iron was added. It was claimed that these shell, by bursting into fine fragments upon exploding, were more effective against troops than all-steel shell, because the fragments of the latter were larger. We adopted this shell also and produced it experimentally. In contour it was a compromise between the old cylindrical shell and the extreme streamline type and was easier to make than the latter.
| To Jan. 1. | 1918 | Total. | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Jan. | Feb. | Mar. | Apr. | May. | June. | July. | Aug. | Sept. | Oct. | Nov. | Dec. | |||
| Calibers for American Expeditionary Force program. | ||||||||||||||
| 75-mm. gun H. E. | 235 | 287 | 809 | 1,168 | 1,122 | 1,175 | 790 | 5,586 | ||||||
| 75-mm. gun shrapnel | 20 | 121 | 124 | 483 | 888 | 1,011 | 1,049 | 730 | 732 | 802 | 1,057 | 812 | 738 | 8,567 |
| 75-mm. gun gas | 188 | 164 | 213 | 15 | 580 | |||||||||
| 75-mm. A. A. shrapnel | 92 | 97 | 185 | 134 | 126 | 634 | ||||||||
| 3-inch A. A. shrapnel | 11 | 59 | 2 | 72 | ||||||||||
| 4.7-inch gun H. E. | 32 | 45 | 43 | 46 | 166 | |||||||||
| 4.7-inch gun, shrapnel | 9 | 9 | 14 | 17 | 18 | 23 | 35 | 23 | 38 | 29 | 28 | 15 | 19 | 277 |
| 5-inch S. C. gun H. E. | 7 | 5 | 12 | |||||||||||
| 6-inch S. C. gun H. E. | 2 | 1 | 36 | 23 | 62 | |||||||||
| 155-mm. gun H. E.[21] | 9 | 33 | 51 | 98 | ||||||||||
| 155-mm. howitzer H. E.[21] | 11 | 113 | 193 | 119 | 173 | 140 | 749 | |||||||
| 155-mm. shrapnel | 12 | 22 | 66 | 41 | 93 | 234 | ||||||||
| 8-inch howitzer H. E. | 91 | 8 | 99 | |||||||||||
| 9.2-inch howitzer H. E. | 13 | 8 | 24 | 3 | 48 | |||||||||
| 240-mm. howitzer H. E. | 2 | 2 | ||||||||||||
| 8-inch S. C. gun H. E. | 20 | 11 | 31 | |||||||||||
| 10-inch S. C. gun H. E. | 20 | 50 | 4 | 11 | 85 | |||||||||
| Total | [22]29 | [22]130 | [22]138 | [22]500 | [22]906 | [22]1,034 | 1,321 | 1,051 | 1,984 | 2,548 | 3,062 | 2,570 | 2,024 | 17,297 |
| Calibers for use in United States only. | ||||||||||||||
| 2.95-inch mountain gun H. E. | 22 | 22 | ||||||||||||
| 2.95-inch mountain gun shrapnel | 37 | 9 | 14 | 2 | 62 | |||||||||
| 3-inch F. G. H. E. | 333 | 73 | 212 | 142 | 128 | 95 | 3 | 1 | 84 | 1,071 | ||||
| 3-inch F. G. shrapnel | 957 | 164 | 231 | 174 | 55 | 60 | 15 | 1,656 | ||||||
| 3.8-inch howitzer H. E. | 3 | 3 | 2 | 2 | 1 | 11 | ||||||||
| 3.8-inch howitzer shrapnel | 12 | 1 | 13 | |||||||||||
| 4.7-inch howitzer H. E. | 14 | 4 | 5 | 1 | 1 | 1 | 1 | 12 | 39 | |||||
| 4.7-inch howitzer shrapnel | 4 | 23 | 5 | 8 | 10 | 10 | 60 | |||||||
| 6-inch howitzer H. E. | 20 | 1 | 3 | 24 | 35 | 83 | ||||||||
| 6-inch howitzer shrapnel | 1 | 3 | 4 | |||||||||||
| Total | 1,398 | 246 | 448 | 342 | 224 | 160 | 20 | 34 | 107 | 10 | 10 | 22 | 3,021 | |
| Grand total | 1,427 | 376 | 586 | 842 | 1,130 | 1,194 | 1,341 | 1,085 | 2,091 | 2,558 | 1,072 | 2,592 | 2,024 | 20,318 |