The Intrinsic Accuracy of Handgun Actions
By Chuck Hawks
Intrinsic accuracy refers to the mechanical accuracy potential of a firearm. Practical accuracy refers to how accurately a human shooter can shoot a firearm. This article is about the intrinsic accuracy inherent in the design of the common types of handgun actions.
To maximize intrinsic accuracy, a handgun's design should keep the barrel, chamber, sights and grip frame in a fixed, rigid and unmoving relationship to each other. These are the key factors affecting the intrinsic accuracy of the various types of actions, assuming they are correctly made and assembled. Let's examine the various common handgun actions, from best to worst potential intrinsic accuracy.
1. Single Shot Target and Hunting Pistols (Bolt, Falling Block and Break-Open Actions)
The most accurate of all handguns are essentially single shot bolt action or falling block rifles cut off at both ends. An example would be the trend setting Remington XP100, a bolt action. The chamber is machined into the breech end of the barrel and the sights and stock (grip) are fixed and unmoving in relation to each other and the barrel. Only the breechblock (bolt) moves to load/unload a cartridge and its lock-up is extremely strong and positive to precisely maintain headspace from shot to shot.
These pistols based on rifle actions can be chambered for practically any rimfire or centerfire cartridge, including rifle cartridges. It doesn't get any better than this and almost all bench rest pistols (the most accurate of all handguns) are of this type.
Just behind in intrinsic accuracy are the break-open action pistols, epitomized by the T/C Contender. This design has most of the same advantages as the bolt action pistols, as the barrel, chamber and sights are all fixed in relationship to each other. The difference is that the action is manually pivoted open to load/unload, so the grip frame is moved in relation to the rest, but not during firing.
The break-open action is only slightly less intrinsically accurate than bolt and falling block actions and for most purposes, including handgun hunting, these large single shot pistol actions may be lumped together. They are designed to accept telescopic sights and are usually so equipped to take maximum advantage of their long range accuracy potential.
2. Blowback Action (Target and Hunting .22 Rimfires)
Target .22 rimfires today are typically blowback operated semi-autos and this is the type of action used in ISU/Olympic target pistols. The most popular example of the type would be the Ruger .22 Target in its many variations.
Look at one of these and you will see that the chamber is machined into the breech end of the barrel, while the receiver, sights and grip frame are all fixed and unmoving in relation to the barrel and each other from shot to shot. The only part that moves when the pistol is fired is the breechblock. The breechblock is held closed by inertia and a powerful recoil spring, rather than positively locked closed, as it would be in a bolt action or falling block design. Blowback target .22s are the cream of the autoloading crop and are second only to the cut down rifles masquerading as handguns in intrinsic accuracy.
Blowback actions are also used for .22 rimfire pocket pistols and plinkers, as well as for centerfire calibers ranging from .25 ACP to .380 ACP. While the basic method of blowback operation remains the same, the design and construction of most of these pistols is such that the action's intrinsic accuracy potential is not realized. Unlike extremely precise match .22s or hunting handguns, these inferior blowback pistols are designed for conceal-ability and/or for sale at a low price point. The result, not surprisingly, is inferior accuracy.
3. Gas Operation
Gas operated semi-automatic rifles can be very accurate and the same potential exists for autoloading pistols. Properly designed, the chamber is integral with the barrel and the barrel, sights and grip frame are all fixed. Only the bolt moves backward and forward when the gun is fired. Unfortunately, for technical reasons, gas operated pistols are very seldom seen and have never been commercially successful. They remain a curiosity.
Revolvers are one of the two mainstream handgun types, the other being short recoil operated autoloading pistols. Of these two types, the solid frame revolver is intrinsically more accurate.
The design of modern revolvers keeps the barrel, sights and grip frame in fixed and rigid alignment. (The exception would be the obsolete top-break revolver design, which is seldom seen today.) As the cylinder turns from shot to shot, only the chamber moves in relation to the rest of the gun. This multiple chamber issue is why the best target .22 rimfire autoloaders are slightly more accurate than the best .22 target revolvers. However, the design of typical swing-out cylinder DA (such as the Colt Python) and Peacemaker style SA (such as the Ruger Blackhawk) revolvers is inherently accurate.
Revolvers are equally adaptable to rimfire and centerfire cartridges, including the most powerful magnum calibers. This combination of versatility, power and accuracy makes revolvers the choice of most handgun hunters. (Hunting is a sport that requires highly accurate handguns.) Revolvers specifically intended for hunting, such as the Ruger Super Blackhawk Hunter, are typically designed to accept optical sights. Revolvers are also the most accurate handguns normally carried in holsters.
5. Short Recoil Operation (Tilt-Barrel)
Georg Luger's famous P-08 pistol used a short recoil toggle action that is intrinsically more accurate than the tilt-barrel type of recoil operation favored today, but the Luger became obsolete due to its labor intensive design. Germany losing two World Wars probably didn't help, either.
The great John Browning pioneered the very successful tilt-barrel short recoil action for autoloading pistols that is used in almost all modern autoloading pistols chambered for high pressure centerfire cartridges. (Cartridges more powerful than the .380 ACP.) This type of action can be made compact and reliable. However, intrinsic accuracy is not among its advantages. It is the least intrinsically accurate of all common handgun actions.
The chamber is machined into the breech end of the barrel, as with other autoloading actions. Unfortunately, when fired, the barrel moves in relation to the slide (where the sights are located) and both move in relation to the grip frame. Basically, in a tilt-barrel action, everything moves in relation to everything else, the worst possible situation for intrinsic accuracy.
A tilt-barrel action can be made reasonably accurate if close attention is paid to achieving the tightest possible tolerances between all of the moving parts. Unfortunately, reducing the operating tolerances often has the unintended consequence of degrading reliability.
Upgrading the accuracy of "combat" competition Model 1911 pistols (the most famous of John Browning's tilt-barrel designs, at least in the US) has become a cottage industry and the cost can run into hundreds of dollars. Regardless, the results are basically "Band-Aids" applied to a type of action that is inherently inferior in intrinsic accuracy.
The better tilt-barrel pistols today (Glock, SIG, Browning, Beretta, Ruger, Kahr, Colt, etc.) are usually sufficiently accurate for short range personal protection, which is typically their intended purpose. If you are interested in precision marksmanship beyond, say, about 30 yards, some other type of action is probably a better choice.
Copyright 2014, 2016 by Chuck Hawks. All rights reserved.