It’s been nearly a month since I (Craig) took up writing about how the US Army’s artillery evolved from the start of the 20th century. Real world stuff distracts me from this important work! In that first post I outlined the (sorry) state of affairs in the field artillery prior to 1914. The best field pieces in the US Army were M1902 3-inch field gun (adapted from a German design) and the M1906 4.7-inch field gun, with honorable mention to the Model 1907 4.7-inch howitzer. While the 3-inch gun equipped batteries on General John Pershing’s Mexican expedition (1916-17), developments in Europe indicated the weapon was not sufficient for a larger, overseas war.
American pride, and preferences of the Ordnance Department, necessitated a domestic design which proceeded through several prototypes to become the M1916. So American gun designers started with the most advanced carriage design possible, with a split trail. A few foreign designs (notably the Italian M1911 75mm) had adopted this layout. But concerns about the carriage strength held back further adoption. Keep in mind in the early 20th century metallurgy still had some ways to go. On a pole trail or box trail carriage, the junction of the axle and trail is easily braced. On a split trail, the junction is made by some form of hinge and thus by nature a weak point to the system.
Nonetheless split trails offer tactical advantages such as wider traverse and higher elevations for the gun tube. The old M1902, on a pole trail carriage, had an elevation range between +15° and -5° and a traverse of 8°. The M1916 3-inch gun boasted an elevation between +53° and -7°, with a traverse of 22.5° left or right. The greater range of motion allowed gunners to switch targets, or stay with a moving target, without repositioning the gun as often. And, oh-by-the-way, place high angle fire on a target otherwise shielded by earthworks or terrain.
For ammunition, the Americans initially preferred the 3-inch caliber of the M1902. This same caliber (roughly 76mm) offered some compatibility with seacoast weapons then in service. Although the M1916’s shells weighed only 13.7 pounds, compared to the 15 pound shell of the M1902, the new gun ranged to 9,590 yards.
Then the project hit the morass often encountered as the directors strive for “perfect” over “good enough.” In order to lessen the stress on the carriage and at the same time take advantage of the superior gunlaying options, the design team adopted a rather complicated recoil system. Initial designs used a hydro-spring system. But this failed to return the gun to firing positions when operating at high angles. So the design team scrapped that and worked on a hydro-pneumatic recoil system. However, lacking extensive experience with such systems, the Americans floundered. Ultimately, the Americans contracted a French designer who for the most part just reproduced an existing hydro-pneumatic recoil system then in use on his country’s guns. And to top it off, initially no American manufacturers were allowed to produce the system, so the first batches were fabricated in France. But that was not the end of problems for the M1916.
The M1916 used a simple vertical sliding breechblock and offered the gun crew a relatively compact work area. Or in other words, the crew was cramped together in between the trails in order to work the piece! As near as I can tell, the Ordnance Department simply shut out the artillerists from design input.
Furthermore, in order to provide strength and mount the elaborate recoil system, the designers wanted a one piece pedestal to support the cradle, gun, and recoil system. After casting trials, this design failed to meet manufacturing standards. So once again the designers made modifications. The new mount incorporated several cast components. By this time the year was 1917, America was entering the war, and no M1916s were ready. The crash program had crashed, but nobody was willing to admit such.
Entry into the war brought another design change – a change of a single millimeter – but a significant change translating to more delays. Faced with the need to equip a vastly expanded army, the US needed to acquire not only field guns but also piles of ammunition. To avoid potential SNAFUs with a proliferation of calibers, the Army agreed to use French ammunition for the lighter field pieces. So the M1916 was re-chambered for the French 75mm caliber then in widespread use, down from the 3-inch or 76mm. That single millimeter represented changes to the chamber dimensions, the recoil system, and carriage. Although minor in scope, these were changes introduced to a weapon system at an advanced development state. Of note, the new ammunition, firing a 13.5 pound shell, increased the range to 12,400 yards.
Not until March 1918 did the first example go to France to receive its recoil system. Arriving later that year, the first gun went through extensive trials. Firing trials went well, but the carriage itself could not handle extensive cross country movement. More modifications strengthened the carriage and reduced play in the traversing system. The advanced carriage design with advanced recoil system along with the multitude of design modifications lead not to the perfect weapon, but rather an unacceptable one.
The final design weighed a respectable 3240 pounds on the carriage. Finally put into full production, the Army received about 250 of the M1916 75mm guns by December 1918. But at that point the war was over. Looking at the sad story of the M1916, many would call it the “Crime of 1916.” It was, for all purposes, the “SGT. York Project” of the real Sergeant York’s time.
After the war the cash strapped Army worked with the weapons on hand. The M1916 received some refinements during the 1920s and 1930s. Some of the guns went to the coastal artillery for use as sub-caliber training devices for the big gun crews. At least one was tested as an anti-aircraft gun, mounted on a truck (part of an American preoccupation for multi-purpose guns during the inter-war years). Others received pneumatic wheels and updated brake systems for high speed towing. In 1940, some of these M1916s finally got to Europe – purchased by the British who were desperately short of anything that could shoot. In British service these guns received the designation “Quick Firing 75mm ‘S’ Mk 2.” The Mk 2s armed home guards and defended beaches, but scarcely fired a shot in anger. A handful remained in the US, used for training in those early war years.
With the failure of the M1916, the US Army turned to other, foreign designs to equip the artillery batteries sent to France during World War I. I’ll look at those next.
(Color photos are from the Flickr photostream of Daniel DeCristo and are part of a larger set of photos taken at the Fort Sill Artillery Museum.)