As outlined in the last post on this thread, the American M1916 field gun, be it a 3-inch or 75mm caliber, was a design project disaster. As mentioned in the scope of the M1916 development crisis, upon entry to war the US Army required a major increase in field artillery equipments. This was not only due to the rapid expansion from a near microscopic peacetime army to that of an expeditionary force, but also due to some doctrinal changes.
Given the allied experience of 1914-1916, any American force entering the trenches required more field guns than previously allocated to divisional formations. The nature of warfighting in that theater required greater densities of artillery. Prior to World War I, allocations of artillery were expressed in terms of the number of infantry troops supported. In the American plans, two competing schemes emerged. The 1911 Greble Board (named for it’s chair, Lt. Col. E. St. John Greble) figured 3 1/4 guns per thousand infantry.
As war experiences came in from the combatants engaged in World War I, another artillery board – the Treat Board – reassessed the needs of the Army should it become involved with the war. While the Greble Board appeared somewhat conservative in allocations, the Treat Board advocated for a lavish five guns per thousand infantry. By comparison, starting the war in 1914, the British employed 6.8 guns per thousand infantry, the Germans reached a ratio of 6.4, and the French were using 4.6 guns per thousand infantry. By 1916 all combatants were employing more than six guns per thousand infantry for quiet sectors, and between eight and twelve for active sectors! Clearly at the entry into war (1917) the US Army had to increase artillery allocations.
In June-July 1917 a board of officers chaired by Colonel Chauncey Butler, Quartermaster Corps, toured the allied armies. Representing the field artillery were Colonels Charles P. Summerall and Dwight E. Aultman. Interestingly, no representative of the Ordnance Corps attended the traveling board. After visiting French and English commands in the combat zone, the Butler Board submitted a lengthy report suggesting operational, organizational, and doctrinal changes based on the war situation in Europe. In his portion of the report Summerall, the senior artillery colonel, pushed for a major increase in artillery allocations for the field formations:
- Division artillery – two regiments of 3-inch guns (12 batteries), 1 regiment of howitzers(six batteries) either 3.8-inch or 4.7-inch.
- Corps artillery – one regiment of 4.7-inch rifles (six batteries), one regiment of 6-inch howitzers (six batteries), one regiment with a mix of 6-inch rifles (four batteries), 8-inch howitzers (one battery), and 9.2- or 9.5-inch howitzers (one battery).
- Army artillery park (one per six divisions) – eight 12-inch railway guns, eight 12-inch railway howitzers, four 16-inch railway howitzers.
To support the American intent for 20 divisions in France, this plan required 2400 3-inch guns, 1200 light field howitzers, 480 4.7-inch guns, 480 6-inch howitzers, 372 6-inch guns, and around 100 each of the 8-inch howitzers, 9.2/9.5-inch howitzers, 12-inch guns, and 12-inch howitzers, along with fifty 16-inch howitzers. Reality was the Americans had about a tenth of this ordnance on hand. Feeding these guns, Summerall proposed accumulating 15,000 rounds per 3-inch gun; 10,000 rounds for each 3.8- or 4.7-inch howitzer; 8,000 rounds for the 6-inch guns and howitzers; 5,000 rounds for the 8-inch howitzers.
Summerall felt each class of gun had a preferable role in combat. This employment was influenced by British thinking. The 3-inch guns would provide rolling barrages, wire cutting, and fire on enemy counterattacks. The light howitzers would fire gas and smoke shells, conduct counter-battery fire, and opportunity fires. 6-inch guns would focus on enemy communication centers, balloon concentrations, and conduct counter-battery missions. The 6-inch howitzers fired wire cutting missions and also targeted enemy machine guns. The larger guns and howitzers would focus on enemy gun positions and counter-battery work.
The plan looks fine, from a 95-years gone-by perspective – but perhaps a bit archaic with the “anti-balloon” and “wire cutting” missions. But just as today’s Army proceeds through PowerPoint fueled meetings, the Army of 1917 convened boards. General John Pershing, soon after arriving in France to stand up the American Expeditionary Force (AEF) headquarters, had established an “organization board” to set standards for the new command. While the Butler Board was still in Europe, called for a conference between the boards. Although the conference agenda covered many aspects, perhaps the most important was to set the corps formations around two infantry divisions, instead of three. This of course had an effect on the allocation of artillery.
In terms of armament, Pershing’s board preferred French 155-mm howitzers (which they called 6-inch) in place of the lighter 3.8- or 4.7-inch models. Pershing’s staff also saw no need for the larger 8-inch howitzers below the Army level, opting for 4.7-inch and 6-inch guns in the Corps artillery. In short, Pershing’s board reduced the number of artillery tubes needed for the twenty division AEF – 1080 3-inch guns, 480 155mm howitzers, 120 4.7-inch guns, 408 6-inch guns, and 288 of the larger howitzers. As for the heavy rail artillery, the AEF only wanted forty 10-inch guns and thirty 12-inch mortars. This reduction cut in half the density of guns desired by Summerall. The AEF did, however, add a battery of trench mortars to each infantry division and a battalion of the same weapons at the corps level.
While personally I’d have preferred Summerall’s plan, at least the AEF had established an artillery organization by July 1917. And like all plans, there is the test of reality. The AEF needed about 2700 artillery pieces of all calibers, not counting spares and reserves. Even if those numbers sat in some holding area in the U.S., planners had to consider shipping space which was already overloaded just getting 20 divisions worth of troops to France. Considering the ammunition supplies needed for these guns, and Summerall’s estimates proved sound for major operations, the AEF needed even more shipping space. A series of decisions and compromises over shipping forced several modifications to the overall artillery plan. Long story short, the AEF would use predominately foreign-made artillery, initially at least firing quantities of foreign-made ammunition.
I’ve already mentioned the change from 3-inch to 75mm for the field gun. For similar reasons, the adoption of the French Schneider M1917 155mm howitzer made perfect logistical sense. The Americans also opted for the French GPF M1917 155mm gun (the “6-inch gun” requested by the AEF). From the British, the AEF would receive 6-inch guns, 8-inch howitzers, and 9.2-inch howitzers. In addition, the AEF obtained a small assortment of French heavy guns, some of which used early self-propelled mountings.
Although a few field guns of American manufacture arrived in France, the most significant contribution American made contribution to the artillery park were several railroad guns stripped from the coastal fortifications (and from Navy stocks for good measure).
But that is not to say American industry didn’t try to supply the AEF. Had the war continued into 1919, the weight of American production would have been felt. Nearly every caliber of gun used by the AEF was either in production or had plans for production in the US as the war drew to a close. I’ll take a look at some of those types next, with particular mind to how those guns influenced the designs used in World War II.