An oft cited generalization in regard to the Cavalry during the Civil War involves the use of repeaters or breechloaders, which gave the troopers some advantage in firepower. And often you’ll see reference to the Army Ordnance Department resisting the adoption of repeaters, citing “ammunition expenditure.”
In Cavalry Tactics, Alonzo Gray offered four vignettes to describe the nature of ammunition expenditure and the firing line. The first came from Lieutenant Colonel George A. Purington, 2nd Ohio Cavalry. The report cited discussed the operations of May 30, just before the Battle of Cold Harbor, where the cavalry was pushed forward to seize positions in advance of infantry movements:
… and here allow me to call your attention to the necessity of having some organized system of ordnance sergeants or men detailed, whose duty it shall be to keep cavalry commands well supplied with ammunition during engagements. Men armed with the breech-loading weapon will necessarily fire a greater number of rounds than those armed with a muzzle-loading piece, and it is utterly impossible for a cavalry man to carry more than from 60 to 80 rounds upon his person, and when dismounted and away from his horse this supply can be easily exhausted in a few hours’ firing. In this case my regiment expended its ammunition in the battle of May 31.
So once again we encounter that old equation – how much can a soldier… or in this case a trooper… carry? In this case, the regimental commander felt that was only 60 to 80 rounds at most.
And how long would that last? “… easily exhausted in a few hours’ firing.”
Infantry types will tell you each member of their line was limited to between 80 and 100 rounds, practically speaking – forty rounds in the cartridge box and a few other packages in pockets or haversacks. So with good fire discipline, one might expect the “time on the line” to be roughly equal between cavalry and infantry, for a skirmish situation.
But there’s more to this than simply counting the number of bullets. First off, where would a trooper or soldier seek resupply? From the trains of course. Infantry trains can normally follow close behind the line of march, save instances of forced or rapid marches. And even then only a few hours might be expected.
Cavalry, on the other hand, might operate for days without the encumbrance of the trains. For example, the four days that Brigadier-General H. Judson Kilpatrick’s cavalry operated towards Millen and back, November 26-29, 1864. But of course, the trooper had a horse on which more ammunition might be carried. Still, as Purington alludes to, the carbine was best employed on foot which put the horse out of reach.
A second problem was that not all bullets are the same. Things that fit down the muzzle of a three-band rifle are not apt to fit the carbine slung over the trooper’s back. The Cavalry didn’t just need any ammunition. They needed their ammunition, as Purington continued:
At daylight details were sent to train, but no ammunition of that caliber (No. 54) could be obtained. Captain Weeks, in command of detail, with great promptness immediately started for our own train, some 9 miles distant, to obtain a supply, making trip back to Hanover Court-House, thence to Ashland, 27 miles, each man loaded with 85 pounds ammunition, in less than one half day, and even then hardly arrived in time, as three boxes were captured by the enemy before we could issue it to the men.
In one paragraph, both of the factors I mentioned above. Half a day to haul ammunition from the trains back to the front. Oh, and part of that was captured before the troopers could get the boxes open. How tight was that situation?
And I feel warranted in saying that had this ammunition not arrived, and with our already too small force weakened by the withdrawal of my regiment, the consummate bravery of the brigade could not have prevented serious disaster.
Gray went on to cite another report filed a year later from Colonel Alexander Pennington, who commanded First Brigade of Major-General George A. Custer’s division during the Appomattox Campaign. In a similar situation to Purington’s, Pennington dispatched a mounted detail to secure ammunition then distribute to the battle line at Five Forks, April 1, 1865.
As a negative example, Gray mentions that Major-General Philip Sheridan withdrew from Trevillian Station for want of ammunition. Though one might contend that Sheridan withdrew from that battle for several reasons… the want of ammunition being just that cited with most clarity (how’s that for being kind?).
From these three sources, Gray advanced the comment:
A soldier should carry enough ammunition on his person to fight at least one battle. A cavalryman may have ammunition on his horse, which ammunition, under most circumstances, will be available. It will seldom be possible to bring ammunition from the squadron wagons to the firing line, but where horsemen can approach the firing line from the rear under cover, ammunition can be supplied.
On the “modern” firing line, we refer to the number of rounds carried in the tank or infantry fighting vehicle. That determines the number of targets the unit might engage and thus the amount of time the vehicle (and crew) can remain engaged without rotation. Of course there are other factors that I could detail here, but for the moment just focusing on the ammunition supply. An M1A2 tank carries forty-two rounds of main gun ammunition. The M1A2 crew might fire six or more rounds per minute, but in combat situations that would be lower for need to acquire and reengage targets. Perhaps, in a pressed situation the crew would burn through those 42 rounds in an hour. More likely a few hours (even then assuming continuous combat, which is not common in the modern combat environment). After those are “sent down range” the tank is basically a mobile fortification with only machine guns. While the troopers of 1865 might be resupplied with someone dragging ammunition boxes up from the rear, an M1A1 must be loaded in a rear area where the handlers are not exposed to fire.
So, you might say this factor of ammunition expenditure and resupply is still a factor… even in a mechanized army with computerized cannon (smoothbore, mind you!) firing armor piercing ammunition. After all 42 rounds and “a few hours’ firing” are somewhat constants for the troopers… regardless if the mount eats grass or JP-8 fuel.
Oh… and I did say Gray cited four sources, yes. The forth was Frederick Whittaker’s Volunteer Cavalry, Lessons of the Decade. That source deserves separate treatment … all to follow shortly.
(Citations from OR, Series I, Volume 36, Part I, Serial 67, page 895; Alonzo Gray, Cavalry Tactics, as Illustrated by the War of the Rebellion, Fort Leavenworth, Kansas: U.S. Cavalry Association, 1910, page 155.)