It is popular to attribute the victory in the American Revolution to the citizen snipers armed with rifles. Historic reenactors are quick to point out that this isn’t so, but the popular perception of rifles as superior to smoothbores remains. The topic often comes up when people compare government enforcers with short-range submachine guns to hunters with longer-range weapons and good camouflage skills. Let’s look at the accuracy of that perception.
A typical British “Brown Bess” musket threw a 545-grain .69-caliber ball at 1000fps. Trained troops could fire three shots per minute. The cost of that ballistic splendor was limited number of shots carried (usually 24) and abysmal accuracy. Hitting a man-sized target beyond 50 yards was very unlikely. On the plus side, the gun had enormous stopping power due to the sheer size of the musket ball. Moreover, the main casualty-producing factor was usually the formidable bayonet.
The hardy frontier rifleman operates the weapons optimized for hunting rather than for close combat. Depending on the rifle, the caliber varied from .36 to .45, providing initial muzzle velocity of 1200-1300fps with ball as light as 65 grains and as heavy as 125 grains. For comparison, a single 000 buck pellet is as fast at the muzzle, weights about 70 grains and its lead has additives for improved hardness. The initially higher muzzle velocity dropped off considerably quicker with round ball ammunition than with modern conical bullets, so even the spin-stabilized .36 caliber rifle bullet had unimpressive terminal performance at extreme range. Depending on the skill of the shooter, the extreme range was from 100 to 200 yards. The trouble with the flintlock rifle was the slow rate of fire, a single shot every minute at best. Despite the lighter weight, rifles were also physically strenuous to shoot, as the soldier had to stuff the tight-fitting bullet down the rifled bore with arms raised high. Loading a musket was physically easier and quicker, but muskets had stronger recoil. The rifles of the American volunteers seldom had bayonet mounts, so they could fire one or two shots only before British regulars could walk up to them and retaliate with bayonets. The few occasions where rifles gave considerable advantage to the Americans were when the British infantry couldn’t reach their foes on foot and had to shoot it out from long range. Without artillery or the opportunity to deploy cavalry, they were at a disadvantage.
The main factor limiting the effectiveness of musket fire was not its inherent inaccuracy. One problem came from the vast amounts of gray smoke covering the battlefield. Another, more serious issue was the nature of the flintlock ignition. After the trigger pull, the shooter had to wait up to 1/15 of a second for the priming charge to ignite the main main powder charge. In that time, burning powder grains and hot fragments of flint and frizzen sparks flew dangerously close to the shooter’s eyes. No wonder most soldiers preferred to turn away from this hazard!
Flintlocks have a high rate of misfires under the best conditions. In wet weather, the bayonet becomes a more reliable tool than the firelock. Therefore, while a single hunter armed with a long-range rifle can successfully ambush a single regular with either a musket or a submachine gun, a trained small unit can usually maneuver by fire and get the civilian defenders in range for automatic fire, grenades, or bayonets. When getting close is impossible, artillery often does the trick. Because of those considerations, the American forces of the 1770s eventually adopted the conventional tactics and armaments of the British and won as much on the field of battle as by skilled diplomacy. The long rifles of Pennsylvania were a factor in the victory, but hardly the paramount reason for the success of the secession.
Why do were view rifles as so superior to the smoothbores in combat? My guess is that perception has more to do with the observations of the Crimean War and the American Civil war. In both conflicts, soldiers used flintlock smoothbores against percussion rifles loaded with Minié balls. A percussion rifle is quicker to load, easier to shoot (no upflash!). Undersized hollow-base conical Minié balls load as rapidly as a round ball, and they can expand to seal the bore on firing to retain velocity much further downrange. However, a .58 caliber Enfield rifled musket of 1853 is not the same as the humble .36 caliber squirrel rifle of 1775 the Americans pressed into use for killing redcoats.