Caplock in the context of "Muzzle loader"

A touch hole, also known as a cannon vent, is a small hole at the rear (breech) portion of the barrel of a muzzleloading gun or cannon. The hole provides external access of an ignition spark into the breech chamber of the barrel (where the combustion of the propellant occurs), either with a slow match (matchlock), a linstock or a flash pan ignited by some type of pyrite- (wheellock) or flint-based gunlock (snaplock, snaphaunce, and flintlock), which will initiate the combustion of the main gunpowder charge. Without a touch hole, it would be nearly impossible to ignite the powder because the only otherwise access into the barrel is from the front via the muzzle, which is obturated by the projectile.

In the later caplock firearms, the ignition sparks are generated by a shock-sensitive percussion cap placed over a conical "nipple", which has a hollow conduit known as the flash channel, that leads into the barrel and serves the same function as the touch hole.

A derringer or deringer is a small handgun that is neither a revolver, semi-automatic pistol, nor machine pistol. It is not to be confused with mini-revolvers or pocket pistols, although some later derringers were manufactured with the pepperbox configuration. The modern derringer is often multi barreled, and is generally the smallest usable handgun of any given caliber and barrel length due to the lack of a moving action, which takes up more space behind the barrel. It is frequently associated with discreet use by women because it is easily concealable in a purse or a stocking.

The original Philadelphia Deringer was a muzzleloading caplock single-shot pistol introduced in 1825 by Henry Deringer. In total, approximately 15,000 Deringer pistols were manufactured. All were single-barrel pistols with back-action percussion locks, typically .41 caliber with rifled bores and walnut stocks. Barrel length varied from 1.5 to 6 in (38 to 152 mm), and the hardware was commonly a copper-nickel alloy known as "German silver".

In firearms terminology, an action is the functional mechanism of a breechloading firearm that handles (loads, locks, fires, extracts, and ejects) the ammunition cartridges, or the method by which that mechanism works. Actions are technically not present on muzzleloaders, as all those are single-shot firearms with a closed off breech with the powder and projectile manually loaded from the muzzle. Instead, the muzzleloader ignition mechanism is referred to as the lock (e.g. matchlock, wheellock, flintlock, and caplock).

Actions can be categorized in several ways, including single action versus double action, break action versus lever-action, pump-action, bolt-action, among many other types. The term action can also include short, long, and magnum if it is in reference to the length of the rifle's receiver and the length of the bolt. The short action rifle usually can accommodate a cartridge length of 2.8 in (71 mm) or smaller. The long action rifle can accommodate a cartridge of 3.34 in (85 mm), and the magnum action rifle can accommodate cartridges of 3.6 in (91 mm).