A breechloader is a firearm or artillery piece in which the user loads the ammunition from the breech (rear) end of the barrel. The vast majority of modern firearms are breech-loaders.
Before the mid-19th century, most guns were muzzleloaders, guns loaded from the muzzle (front) end of the barrel.
A musket is a muzzle-loaded long gun that appeared as a smoothbore weapon in the early 16th century, at first as a heavier variant of the arquebus, capable of penetrating plate armour. By the mid-16th century, this type of musket gradually disappeared as the use of heavy armour declined, but musket continued as the generic term for smoothbore long guns until the mid-19th century. In turn, this style of musket was retired in the 19th century when rifled muskets (simply called rifles in modern terminology) using the Minié ball (invented by Claude-Étienne Minié in 1849) became common. The development of breech-loading firearms using self-contained cartridges, introduced by Casimir Lefaucheux in 1835, began to make muskets obsolete. The first reliable repeating rifles, the 1860 Henry rifle and its 1866 descendant the Winchester rifle, superseded muskets entirely. Repeating rifles quickly established themselves as the standard for rifle design, ending the era of the musket.
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