The United States Army came into being on the 14th of June 1775 when the Second Continental Congress affirmed the creation of a Continental Army and appointed George Washington as its commander-in-chief. After Washington whipped the Massachusetts Militia into shape, the core of an institution was born. In the 250 years since then, the arms and the training around it has evolved well beyond the glacial pace of time.
For much of the Army’s existence, how the warfighter handles his arms and ammunition dictated how he could fight alone and as part of a team, how he could exploit his adversaries, and how he could shield himself from his deficits. This is a history of small arms ammunition from Boston to Baghdad and beyond.
Powder and Shot: Biting the Bullet in the Musket Era
The smoothbore musket was the long gun of choice for the US Army from its inception until just before the Civil War (1861-65). Muskets differ from rifles due to their smooth bores. Given that these were muzzleloaders that used black powder, smoothbores are easier and faster to load, as black powder residue accumulates. A comparable rifle would get progressively harder to load.
The solution was the smoothbore musket, which had no rifling to get caked up with residue. It was loaded with an undersized lead ball in a paper cartridge that also contained the black powder. This increased the soldier’s rate of fire, but gave less than stellar accuracy. The effective firing range of a smoothbore musket when loaded this way was inside 100 yards, beyond which hitting a point target was less likely.
To increase hit probability, George Washington mandated that the Continental Line’s cartridges be loaded with buck and ball, a cartridge with a .65 caliber musket ball and three 00 buckshot pellets for use in the Army’s French-supplied .69 caliber muskets. This was less accurate than using ball alone, but for shooting at massed formations, the effect was pronounced.
Buck and ball remained the go-to load for the Army until they dispensed with smoothbore muskets for the rifled musket after the Mexican War.
Muskets were the universal weapon, but not the only one. Rifles were used in limited numbers, but were problematic. For the musket ball to spin with the rifling and get the best accuracy, it had to be a tight fit to the bore.
Early rifles used in the American Revolution were personally owned, hand-built models that relied on measured powder charges and balls wrapped in greased leather or linen to get down the barrel. It would not be until the 1792 Contract Rifle that the Army had a uniform rifle, but the slow loading procedure was the same.
The American Civil War: Rifled Muskets and Cartridges
![The Army of the Potomac—A sharpshooter on picket duty. [W. Homer, Esq]](https://inside.safariland.com/wp-content/uploads/2025/05/sharpshooter-civil-war.jpg)
The American Civil War saw countless innovations put to the test. These range from the rifled musket to paper cartridge-firing breechloaders to repeating rifles that fired fixed metal cartridges, similar to those we have today. But instrumental to how we got there is the percussion cap and the Minié ball.
Flintlock guns were standard during the Revolution until the early 1840s. They were prone to hangfires or misfires as the powder used to prime these firearms could become soggy if the soldier did not look after it. Percussion caps offered an action that was more sealed from the elements, but also paved the way for the cartridge.
Percussion caps are small metal caps packed with sensitive explosives that would jet flame when struck. In the case of the muzzleloader, it would send that flame right into the powder charge, discharging it. Later, these explosives were packed into the rim of short brass cases with powder and bullet on top. This gave us the first rimfire cartridge in the .22 Short. Later, formed brass cases with caps in the center of the case head gave us the first centerfire cartridges.
The Minié ball was developed in France but refined in England and the United States. This elongated lead slug was heavier than the lead balls used in muzzleloaders previously. It could carry its energy further and buck the wind better. It was undersized for the bore and easy to load, but it featured a hollow base that could engage a rifled barrel when the bullet was fired.
The rifled musket in the Model 1855, 1861, and 1863 Springfield was the standard issue long gun for the Union during the Civil War. It used percussion caps but was still a muzzleloader that took a paper cartridge. Inside the cartridge was sixty grains of powder and a .58 caliber 500 grain Minie. The rifled musket was just as fast as a smoothbore to load, but could hit a point target at 500 yards and beyond.
Smaller versions of the Minié found their way into self-contained cartridges when paired with caps and a breechloading action that is loaded from the rear rather than the front at the muzzle. The Union cavalry made great use of breechloaders ranging from the paper cartridge firing M1859 Sharps to the lever-action seven-shot Spencer carbine. Unfortunately for the average soldier, the US Ordnance Department could not get rifles like these produced in quantity and was heavily invested in large stockpiles of rifled muskets. But once the war was over, the Army was quick to ditch its muzzleloaders.
By 1873, the US Army adopted the Trapdoor Springfield rifle and the Colt Single Action Army revolvers, chambered in .45-70 and .45 Colt, respectively. This combination would see the Army through for the next 20 years until smokeless powder left the Ordnance Department behind the times.
Smokeless Powder and Hyperspeeds
Small arms ammunition had come a long way from the days of buck and ball paper cartridges, but the propellant remained the same. Black powder was easy to make and an excellent explosive, but in many ways, the guns and ammo of the time were designed to work around black powder, rather than tailoring the powder to work with the firearm.
Black powder produces clouds of smoke and residue. Furthermore, there is a certain point of diminishing returns with black powder when used in firearms. At some point, the amount of powder used in a cartridge case begins to exceed the gains in velocity and power.
All of these factors limited black powder guns to a lower velocity and a trajectory that was parabolic. In the Revolutionary era, a unit needed to close with the enemy to be effective. But using column tactics during the Civil War with rifled muskets taught the Army brass the value of standoff distance. Large-bore cartridges firing long-for-caliber bullets like the .45-70 Government were the best options to stretch the legs of lower velocity black powder rounds.
The deadly game of Keeping Up with the Jones’ was changed when the French came up with smokeless gun powder in 1885, followed by the introduction of the M1886 Lebel rifle. The Lebel’s cartridge had little residue, no smoke, and doubled the velocity over existing cartridges but retained the same striking energy. Higher velocities were also realized thanks to a Swiss invention: the jacketed bullet. This copper sheath over the lead bullet prevented it from melting in the bore.
The world scrambled to find their own smokeless formula and new rifles and handguns strong enough to use it. The Army’s first smokeless rifle was a unique take on the Norwegian Krag-Jorgensen, chambered in .30-40. But problematic tactics during the Spanish-American War (1898-99) and the invention of pointed spitzer bullets in 1906 resulted in the adoption of the M1903 Springfield with an updated .30-06 cartridge. Rifles like the Krag and Springfield were designed with ladder sights and magazine cut-offs so they could be used as a poor man’s artillery at distances beyond 1,000 yards.
Smokeless powder also changed handguns, as the cleaner-burning powder made the semi-automatic pistol and machine gun into a working reality. The lightweight, man-portable Browning M1895 machine gun was not perfect, but it was leagues lighter and truly automatic, unlike the Gatling guns it replaced. While many revolver cartridges survived the jump to smokeless powder, recoil and gas-operated pistols and rifles like the Colt M1911 and Winchester 1907 made their debut.
With the proliferation of autoloading firearms, the pendulum inevitably swung back on an emphasis on volume of fire.
Platform Changes and the Reinstitutionalization of Volume of Fire
Bolt-action rifles remained the mainstay infantry arm up through the Second World War because it was proven and paid for technology, and most armies put greater emphasis on light machine guns to give firepower to the squad while individual riflemen could pick off combatants that threatened the big guns.
Semi-automatic rifle designs existed and were in fairly common use on the commercial market, but producing a rifle that could handle full-powered rifle ammunition reliably was another matter. The one bright spot as the United States entered World War II was the M1 Garand, which succeeded in doing just that. It boasted the same range and power as the ’03 Springfield but gave the soldier more firepower if he needed it.
As the war would prove, the soldier did need extra rounds. Studies from the results of the war proved out two results that would be carried forward into arms and ammunition development. First, the majority of engagements took place inside 300 yards. Second, a higher volume of fire increased the chances of prevailing in a fight. The need for more ammo was obvious, but it did not need to punch out to 1000 yards. It was energy wasted on the shooter’s shoulder and beyond the intended target as well.
Fascist Italy tried its hand at an intermediate 300-yard cartridge with the 7.35 Carcano before the war, but progress was halted due to hostilities. The Germans took the concept full circle with the 7.92 Kurz round in the select-fire STG 44. Likewise, the Soviets developed the 7.62x39mm cartridge and fielded the first SKS rifles toward the end of the war. That rifle was a bridge to the AK-47. While the US Army was well served with the Garand, reliance on a philosophy of full-power ammunition led to inertia as the US entered the Cold War.
Big Bore to Small Bore: The 5.56 NATO Era
During the early Cold War, the Department of Defense oversaw dramatic cuts to conventional forces and emphasized nuclear deterrence. The Ordnance Department, ever the conservative organization, wanted to retain a full-powered battle rifle to fill multiple roles.
In 1957, the Army adopted the M14. It fires 7.62 NATO cartridges and uses detachable 20-round magazines. The 7.62 NATO round itself was shorter than the existing .30-06, which made it easier to use in lighter machine guns and shorter-action rifles. But it retained much of the .30-06’s power. The M14 was a select-fire weapon meant to fill the role of infantry rifle and squad automatic weapon, as well as replace the pistol caliber submachine gun. But in an attempt to do it all, the M14 did none of it well.
The US Air Force, in particular, was dissatisfied with the M14. On the whim of Gen. Curtis Lemay, the Armalite AR-15 in .223 Remington was tested and adopted in 1960. The new rifle was also sent to Vietnam by the Advanced Research Projects Agency to good reviews. The .223 is an intermediate cartridge that is lighter and smaller than the 7.62 NATO cartridge, so the soldier could carry more ammunition and did not have to fight as much felt recoil. It did not have the raw power and long legs of the 7.62 NATO, but the 55-grain FMJ bullet used by the .223 had a unique tumbling characteristic that gave up little in on-target performance.
The Army stood by the M14, and there were even allegations of sabotage in trials to derail the AR-15, but as the war in Vietnam heated up, there were not enough of the imperfect M14s to fully arm all troops. The modular AR, however, could fill that need and was adopted service-wide in mid-1963 as the select-fire M16.
The .223 Remington cartridge was adopted as the 5.56 M193 cartridge in American service. This round served as the basis for different loadings that morphed into the near-identical 5.56 NATO cartridge that continues in service today.
The Latest Efforts: The .277 Fury and hybrid case ammunition
Fast forward to the end of the Cold War, and the realities on the battlefield have changed. The Global War on Terror marked increased use of hard body armor. Furthermore, the going convention of close engagements was challenged in the valleys and passes of Afghanistan, where the 5.56 NATO cartridge proved light.
The pendulum between power and volume of fire has swung back into the power dimension with the Army’s adoption of the 6.8x51mm cartridge in 2022.
The 6.8, otherwise known as the .277 Fury, is meant for the next generation of Army rifles and light machineguns. The new XM7 rifle is based on Stoner’s AR-10 design and has familiar AR controls, but the new round supports a heavy-for-caliber bullet with greater penetrating capacities and flatter trajectories than either the 5.56 or 7.62mm NATO. To help accomplish this, the 6.8 features a hybrid case. Whereas most metallic cartridges use a brass or steel monolithic case, the 6.8 has a steel case head and a brass body bound with an aluminum washer. The brass body achieves lubricity for feeding while the stronger steel rear allows for higher chamber pressures without blowout.
What’s Next for Small Arms Ammunition?
In the 250 years since the inception of the United States Army, the organization has had to balance desires with practical realities. The case is no different with ammunition and the guns that use it. While arms adoption is glacial at the best of times, the Army also had the ability to stick and move when a crisis loomed.
But even the best move was cooled by what was available, what was sustainable, and what personality in the Ordnance Department won out. That battle boiled down to a constant debate over two camps: accuracy and volume of fire. It was true when General Washington ordered the issuance of buck and ball for volley fire during the American Revolution, and it is still true today. No matter which way the pendulum swings, when the Army decides, both military entities and the shooting public worldwide react.
