A muzzleloader is any firearm where the projectile and usually the propellant charge is loaded from the muzzle of the gun. This is distinct from the more popular modern designs of breech-loading firearms. The term "muzzleloader" may also apply to the marksman who shoot muzzleloading firearms. The term of art includes rifled muzzleloaders and smoothbore muzzleloaders. There are several different calibers of muzzleloading firearms. Modern muzzleloading firearms a variety of firing mechanisms. These include sidelock, flintlock and percussion models of the Pennsylvania rifle (after the early 1800s called the Kentucky rifle). Muzzleloading can apply to anything from cannons to pistols. But in modern use the term most commonly applies to black powder small arms. It usually, but not always, involves the use of a loose propellant (like gunpowder) and a projectile, as well as a separate method of ignition or priming.

History 
Some of the earliest muzzleloaders were matchlocks. The matchlock, named for its firing mechanism, was the first invention that made it possible to keep both hands on the weapon and at the same time keep the shooter's eyes on the target. The design allowed a cloth or stick with a flame on the end—called a "match"—to be lowered into a "flashpan" filled with gunpowder which ignited the main charge, firing the gun. Matchlocks appeared in Europe in about 1400. The matchlock mechanism was used to produce muskets. The gun barrels were smooth inside and used round ball ammunition. Those who used muskets were called "musketeers". Very few pistols used this design but some shotguns from this period were matchlocks.
 
In about 1509 the wheellock was the next advance in muzzleloader technology. It did not have a match to keep lit and generated a spark mechanically with a wheel mechanism. But they were expensive to produce and cheaper (by half) so matchlocks remained in use.

It took another 200 years to improve on the matchlock. Marin le Bourgeoys, a Frenchman is credited with inventing the Flintlock mechanism sometime in the 1620s. He was variously an artist, a crossbow maker and a gunsmith (harquebuzier). From 1660 to 1840, flintlock muzzleloading rifles and pistols were used by every European and American army. It produced a spark by a flint striking steel producing a spark and igniting the priming powder. By covering the priming powder until the gun was fired, it would usually work even in windy or damp weather. In 1722, the British Army called for a standard pattern of muzzleloading flintlock musket. The resulting model and its variants were called the Brown Bess. It remained in service until the 1830s.

The percussion cap mechanism was the next great improvement in firearms. It was also called a caplock. The percussion cap was based on the discovery of fulminate of mercury in about 1800. When struck with a sharp blow, mercury fulminate detonates. In 1816, Joshua Shaw, an artist living in Philadelphia, painted fulminate of mercury on the inside of copper caps. He fitted it over a small nipple on the firing hole over the bore. When the hammer struck the percussion cap, the gun fired.  By 1826 they were widely used and had replaced the flintlock.

The percussion cap eliminated the flash pan, flint and frizzen. It added the step of placing a cap on the nipple cone, but it was a real advantage to troops in battle. Percussion caps were quick to load and worked in nearly all weather conditions.

In 1869, the centerfire cartridge was invented. It worked only in breech-loading weapons and together they quickly replaced the muzzleloader in common use.

Mortars 
Modern mortars use a shell with the propelling charge and primer attached at the base.  Unlike older muzzleloading mortars, which were loaded the same way as muzzleloading cannon, the modern mortar is fired by dropping the shell down the barrel. A pin at the bottom fires the primer, which then ignites the main propelling charge.  Both the modern mortar and the older mortar were used for high angle fire.  However, since the mortar is not loaded in separate steps makes its definition as a muzzleloader a matter of opinion. However, in the simplest terms it does load from the muzzle end.

Cannon 

Crude muzzleloading cannons existed in China from about the 12th century, possibly earlier. One of the first weapons used in Europe was the bombard. They were muzzleloaders built in different diameter barrels to fire anything from a small rock to a  cast iron ball. By the 16th century muzzleloading cannons began to replace bombards. Casting had greatly improved in Europe after about 1570. In the early 1500s, French cannons were used to break up masses of men in their campaigns in Italy. The Germans had some of the best gunners in Europe and developed cannon that could hit targets at up to . Next, the Swedish under Gustavus Adolphus developed lightweight cannons that could easily move around the battlefield. He used a cast 4-pounder that weighed about  and could be pulled by just two horses.

In 1742, Englishman Benjamin Robins wrote New Principles of Gunnery where he added science to the field of ballistics. He developed carronades which were short, lightweight muzzleloading smoothbore cannons that could be used on the decks of ships. During the American Revolutionary War, the British had a number of different cannons as well as mortars. Many of the American weapons were captured British cannon.

In 1853 France introduced the Canon-obusier de 12, a 12-pounder capable of firing both shot and shell also called a "Napoleon". The U.S. Army adopted the Napoleon 12-pounder in 1857 as the Model 1857 12-Pounder Napoleon Field Gun. It became the most popular field gun on both sides during the American Civil War. They were ultimately replaced by breach-loading cannons after the Civil War.

References

Other websites 
 Shooting traditional muzzleloaders; YouTube
 Live Fire With a Civil War (muzzleloader) Cannon: YouTube

Firearms
Weapons