Revolver-type weapons are part of the long development of making better multishot weapons. They were partly an attempt to improve on pepper-box type weapons, which used a revolving cylinder with one set of firing mechanisms, but had multiple barrels as well. Firing through a single barrel saved the expense and weight of having the multiple barrels of the pepper-box. Revolvers have remained popular to the present day in many areas, although they have largely been supplanted by semi-automatic magazine-fed pistols such as the M1911 .45 caliber and Beretta M9 9mm, especially in circumstances where reload time and larger ammunition capacity is important.
There have been unique variants, such as the American Civil War-era Le Mat, which had a revolver mechanism for pistol bullets concentric to a single shotgun barrel.
A revolver works by having several firing chambers arranged in a circle in a cylindrical block that are brought into alignment with the firing mechanism and barrel one at a time. A single action revolver requires the hammer to be pulled back by hand before each shot. In a double action revolver, the trigger pull can pull back the hammer as well as release it.
Most commonly, such guns have a five- or six-shot capacity; however, some revolvers have up to a 10-shot capacity (this often depends on the caliber, though different companies produce revolvers in the same calibres with different capacities, due to other design differences), and each chamber has to be reloaded manually. Further reducing capacity is the safety practice of leaving one chamber, the one in line with the barrel empty for carrying the weapon.
This makes the procedure of reloading such a weapon slow (even with the help of such devices as speed-loaders). The alternatives are a replaceable cylinder, a 'speed-loader' which can reload all chambers at once, or a moon clip that holds half or a full load of ammunition and that is inserted along with the ammunition.
Due to the simplicity of design, a revolver is easier to make and has higher reliability than other multi-shot firearms in extreme environments. For these reasons, such guns are the most commonly-owned weapons for personal self-defense and hunting, where their capability to fire powerful ammunition with great accuracy has maintained their popularity.
Famous calibres include the .22 rimfire, .38 Special and .357 Magnum, .44 Special, .44 Magnum and .45 Long Colt. There are many more calibres that were once popular; they were introduced in the era of the 'Old West'. Many of these are still being loaded and used by devotees. These calibres include the .32-20, .38-40, and the .44-40.
Generally lower ammunition capacity and longer reload times have seen revolvers fall out of favour with most police and military users. Famous military revolvers include the Webley, the Colt Single Action Army and the Smith & Wesson 1917. Many police forces still use revolvers for their hostage rescue units.
Revolver technology does live on in other weapons used by the military. Some autocannons and grenade launchers use mechanisms similar to revolvers, and some riot shotguns (e.g., Atchison Assault Twelve) use rotating magazines.
Revolvers can be smaller than automatics of the same caliber, and, when the pistol is to be concealed, may further be reduced in size by shortening the barrel. The Smith & Wesson .38 caliber "Chief's Special" has a 2"/51mm barrel, which reduces accuracy considerably, but most police firing is at very short range. A more typical barrel length is 6"/152mm.
Loading and unloading
The first revolvers were muzzle loading, which meant that each chamber in the cylinder was loaded from the front with loose powder and a bullet. Usually, there was a loading lever attached to the bottom of the barrel that gave the user leverage to force the oversized lead ball into the chamber, which sealed it and held the ball and powder securely in place. The first practical revolvers were caplocks, because the caplock method of priming was the first that was compact enough to make a practical revolver.
The first generation of cartridge revolvers were converted caplock designs. In many of these (especially those that were converted after manufacture), the pin on which the cylinder revolved was removed, and the cylinder taken from the gun for loading. Later models used a loading gate at the rear of the cylinder that allowed one cartridge at a time accessed for loading, while a rod under the barrel could be pressed backwards to extract the fired case. Most revolvers using this method of loading are single action revolvers. Since the cylinder is firmly attached at front and rear of the frame, and since the frame is full thickness all the way around, most large calibre hunting revolvers tend to be single action. Oddly, the loading gate on the original Colt designs (copied by nearly all single action revolvers since) is on the right side, which slightly favors left handed users.
The next method used for loading and unloading cartridge revolvers was the top break design. In a top break revolver, the frame is hinged at the bottom front of the cylinder, and the barrel and cylinder can be rotated to expose the rear of the cylinder. In most top break revolvers, the act of pivoting the barrel and cylinder operates an extractor that pushes the cartridges in the chambers back far enough that fired rounds (which, since the bullet is gone, are shorter than unfired rounds) will fall free. Fresh rounds are then placed into the cylinder, either one at a time or all at once with a speedloader. The barrel and cylinder are then rotated back and locked in place, and the revolver is ready to fire. Since the frame is in two parts, held together by a latch on the top rear of the cylinder, top break revolvers are fairly weak, and can only handle low pressure rounds. Top break designs are nearly extinct in the world of firearms, but they are still found in airguns.
The last and most common method of loading and unloading is the swing out cylinder. The cylinder is mounted on a pivot that is coaxial with the chambers, and the cylinder swings out and down (to the left in all cases, which facilitates right handed shooters). A rod projecting from the front of the cylinder serves as an extractor, and when pressed will extract all fired rounds (as in top break models, the travel is designed to not completely extract longer, unfired rounds). The cylinder may then be loaded, singly or with a speedloader, and closed, where it latches in place. The rotating part that supports the cylinder is called the crane; it is the weak point of swing-out cylinder designs. Allowing the cylinder to flip open and closed with inertia (as is often portrayed in movies and television) will cause the crane to bend, throwing the cylinder out of alignment with the barrel. This lack of alignment is a dangerous condition, resulting in high pressures, bullet damage, and a potential explosion if the bullet becomes stuck. The shock of firing can also put a great deal of stress on the crane, as in most designs the cylinder is only held closed at one point, the rear of the cylinder. Stronger designs, such as the Ruger Super Redhawk, use a lock in the crane as well as the lock at the rear of the cylinder. This provides a more secure bond between cylinder and frame, and allows the use of larger, more powerful cartridges.
In a single action revolver, the hammer is manually cocked, usually with the thumb of the firing or supporting hand. This action advances the cylinder to the next round and locks the cylinder in place with the chamber aligned with the barrel. The trigger, when pulled, releases the hammer, which fires the round in the chamber. To fire again, the hammer must be manually cocked again. This is called 'single action' because the trigger only performs a single action, that of releasing the hammer.
Most double action revolvers may be fired in two ways. The first way is exactly the same as a single action revolver; the hammer is cocked, which advances the cylinder, and when the trigger is pulled, it releases the hammer. Double action revolvers also can be fired from a hammer down position, by just pulling the trigger. In this case, the trigger first cocks the hammer (thus advancing the cylinder) and then releases the hammer at the rear of its travel, firing the round in the chamber. Double action only revolvers lack the latch that enables the hammer to be locked to the rear, and thus can only be fired in the double action mode.
Double action revolvers use a long trigger pull to cock the hammer, thus negating the need to manually cock the hammer between shots. The disadvantage of this is the long, heavy pull that cocks the hammer makes the double action revolver much harder to shoot accurately than a single action revolver (although cocking the hammer of a double action reduces the length and weight of the trigger pull). There is a rare class of revolvers, the automatic revolver, that attempts to overcome this restriction, giving the high speed of a double action with the trigger effort of a single action.
The Webley Fosbery automatic revolver was the first commercial example, introduced in 1901. It was recoil operated, and the cylinder and barrel recoiled backwards to cock the hammer and revolve the cylinder. It was distinctive in that cam grooves were milled on the outside of the cylinder to provide a means of advancing to the next chamber, half a turn as the cylinder moved back, and half a turn as it moved forward. .38 calibre versions held 8 shots, .455 calibre versions 6. At the time, the few available automatic pistols were larger, less reliable, and more expensive. The automatic revolver was popular when it came out, but it was quickly superseded by the creation of reliable, inexpensive automatic pistols.
In 1997, the Mateba company developed a type of recoil operated automatic revolver, commercially named the Mateba Autorevolver, which uses the recoil energy to auto-rotate a normal revolver cylinder holding 6 or 7 cartridges, depending on the model. The company has made several versions of its 'autorevolver', including longer barrelled and even rifle-like variations, usually chambered for .357 Magnum ammunition, but also available in larger calibres like .44 Magnum and .454 Casull.
There is also a combat shotgun based on the automatic revolver principle, the Pancor Jackhammer. It uses a type of gas action to move the barrel forward (which unlocks it from the cylinder) and then rotate the cylinder and cock the hammer.
Elisha Collier developed a flintlock revolver in 1818, and significant numbers were being produced in London by 1822. Samuel Colt received a patent for his revolver on 25 February 1836, and made the first production model on 5 March of the same year.
Famous brands and manufacturers
- Magnum Research
- Smith & Wesson
- Webley & Scott