Armies of the gunpowder age were certainly trained to fire in volleys; this would conserve ammunition and theoretically ensure the greatest impact to enemy morale when loosed.

However, it was often a different story when the rubber hit the road. Even the notoriously disciplined Prussian Army of Frederick the Great, trained to fire by platoons (10 per battalion, one firing after the other), would usually descend into uncontrolled rapid fire in combat. By the time of the Napoleonic Wars, infantry (especially French) are increasingly fighting outside of the usual ranks and files, allowing the common musketeer to take aim and fire at his own pace; John Elting describes the entire front line of an army corps in combat settling into a heavy skirmish line. This allowed the French infantry to outshoot their rivals, while presenting few clear targets for massed volleys.

An important caveat concerns bayonet assaults. When called upon to drive the enemy from their positions, the British would march up to close range, take the enemy's fire, and loose one volley practically into their faces. They would not reload at all after this, but instead rushed upon the enemy with bayonets leveled. The British won numerous actions in the American War of Independence like this, with Americans almost always fleeing from the cold steel. It was recognized that once men stopped moving to reload their pieces, it was quite difficult to get them moving again.

Indeed, in a number of actions during the American Civil War (most famously Upton's assault at Spotsylvania), men would advance with their muskets empty; they would have no choice but to close to bayonet range as quickly as possible, without stopping to fire at all.

Another good illustration of the dynamics of volley fire is the Battle of Fontenoy, between a British-Dutch-German army and the French under Marshal Maurice de Saxe. When the elite British Guards Brigade advanced upon the French Guards, a British officer cordially invited the French to fire the first volley; the French returned the invitation, asking the British to fire first. This wasn't just idle courtesy; it was believed that whoever fired first would be at a distinct disadvantage during an assault. If the attacker fired first, men with empty guns would have to advance into the teeth of an enemy prepared to scythe them down at point blank range. If the defender fired first, likewise the attacker could advance right up into their faces, loose a volley, and charge with the bayonet before they could reload. At Fontenoy, the French were eventually persuaded to fire first, and the volley the British returned at close range wiped out 700-800 men at a stroke.