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Calibers

Along with the type of action, the choice of caliber needs to be made. In rimfire rifles, identical models are available in 22 LR, 22 WMR, and 17 HMR calibers and some are also available in 17 Mach 2. This is by no means the case with handguns, and comparable models are not always available. One outstanding exception is the Ruger Single Six convertible, which comes with one cylinder that chambers the 22 LR and another that chambers the 22 WMR. It is possible to offer a combination such as this even though the bullet diameter for the 22 LR is 0.223” while that for the 22 WMR is 0.224” and the small difference causes no problems. This is a single-action revolver that gives the shooter the choice between two power levels (and price levels in ammunition). Another manufacturer that offers a single-action revolver with two cylinders is Heritage. Some older Harrington and Richardson revolvers offer two cylinders and can be found on the secondary market.

One factor to consider when discussing handgun calibers is the difference in velocity that results from the short handgun barrel compared to that of a rifle. The 22 LR develops maximum velocity while traveling approximately 16 inches in a rifle barrel. If the barrel is longer than about 18 inches, the velocity actually decreases slightly because of being slowed by friction. In a 6-inch handgun barrel, the velocity produced by a given load is somewhat lower than it is when the same load is fired in a rifle. In most cases, there is approximately 125 to 150 ft/sec difference between the velocity produced by a 6-inch barreled handgun and the velocity given by the same load in a rifle. Moreover, because there is a gap between the cylinder and barrel in a revolver (usually 0.002 to 0.008 inches), some gas escapes through this gap and is not used to push on the bullet. As a result, a revolver having a given barrel length generally gives lower velocity than that produced by a semiautomatic having the same barrel length and firing the same type of ammunition. Incidentally, barrel length of a revolver does not include the cylinder in the measurement. The barrel length for a semiautomatic is the distance from the breech to the muzzle.