Plug Bayonets
Plug bayonets were the first type of bayonet fielded by an armed force. They were designed to be used with the matchlock musket. A matchlock, as defined by the Oxford American Dictionary, is "a type of gun with a lock in which a piece of wick or cord is used for igniting the powder." This type of gun was very inaccurate and was in common use in the 17th century. At the time, it was common practice to use a combination of pikemen and musketeers. A pikeman carried a pike, a long spear. To support the pikemen, a musketeer would plug the handle, or hilt, of his knife into the barrel of his musket.
Socket Bayonets
The socket bayonet replaced the Plug bayonet in the late 17th century, and this type lasted until the 20th century. The French were the first to use the Socket bayonet, although the rest of Europe quickly adopted this innovation. The Socket bayonet consisted of a long blade welded onto a 3- or 4-inch steel tube that fit over the barrel of the musket. Unsurprisingly for such a long-service weapon, variations abounded. Around 1715, the bayonet's shape became a standard shape, featuring triangular blades.
Knife Bayonets
Starting in 1800, military forces also used the Sword bayonet, which was simply a sword attached to a rifle. These sword bayonets did not replace the socket bayonet, but were used alongside it. The Sword bayonet evolved into Knife bayonets. Types of Knife bayonets varied from weapon to weapon and army to army. Each, however, featured a sharpened blade attached to a guard and a hilt. The hilt was the handle, and the guard was a piece separating the blade from the hilt in order to guard against an enemy's blade sliding along yours. The guard usually had a large hole on one side called either a Barrel Hole or Barrel Ring, through which the barrel would slide. The hilt would have a slot or button to attach the bayonet to the rifle. These were called Catch Buttons, Thumbpieces, Attachment Slots, Attachment Grooves or Stud Slots.
Bayonets Today
Manufacturers still design bayonets for use with the guns of today. Each gun has a different type of bayonet designed to be used with it. In addition to new bayonets, a community collects old bayonets. They might collect bayonets from one period, or they may collect those from one particular nation or culture.