| .460 Rowland | ||
|---|---|---|
| Type | Pistol | |
| Place of origin | United States | |
| Production history | ||
| Designer | Johnny Rowland, Starline Brass, and Clark Custom Guns | |
| Produced | 1996– | |
| Specifications | ||
| Bullet diameter | .451 in (11.5 mm) | |
| Case length | .955 in (24.3 mm) | |
| Overall length | 1.275 in (32.4 mm) | |
| Primer type | Large pistol | |
| Ballistic performance | ||
| Bullet weight/type | Velocity | Energy |
| 185 gr (12.0 g) JHP | 1,425 ft/s (434 m/s) | 834 ft·lbf (1,131 J) |
| 230 gr (15 g) JHP | 1,250 ft/s (380 m/s) | 798 ft·lbf (1,082 J) |
| 230 gr (15 g) FMJ | 1,250 ft/s (380 m/s) | 798 ft·lbf (1,082 J) |
| 255 gr (16.5 g) Bonded Core HP | 1,100 ft/s (340 m/s) | 685 ft·lbf (929 J) |
| Test barrel length: 5.5 in Source(s): CORBON[1][2] |
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The .460 Rowland is a proprietary cartridge intended to attain .44 Remington Magnum level velocities with a M1911-pattern semi-automatic pistol. The cartridge concept originated with Johnny Rowland, the host of "The Shooting Show". In 1996, Rowland worked with Starline Brass to finalize the physical dimensions of the cartridge, then later with Clark Custom Guns to design a conversion kit for specific versions of the M1911.[3] First production shipments of ammunition and conversion kits were in 1998.
Contents |
The .460 Rowland case is approximately 1/16" (.0625 inches (1.59 mm)) longer than a conventional .45 ACP. However, the overall cartridge length of the .460 Rowland is the same as the .45 ACP as the bullet is seated a bit deeper. This means the practical case capacity for both cartridges is identical. Case length for the .45 ACP is 0.898 inches (22.8 mm) and cartridge overall length is 1.275 inches (32.4 mm). Case length for the .460 Rowland is 0.955 inches (24.3 mm) and cartridge overall length is 1.275 inches (32.4 mm). The purpose of the extended case length is to prevent the high pressure .460 Rowland from being chambered in a standard firearm chambered for the low pressure .45 ACP, similar to the relationship between the .357 Magnum and the .38 Special. The overall cartridge length restriction imposed on both cartridges is established by the cartridge length capacity of the M1911 design.
There are two key elements to the .460 Rowland concept. The first is a sharp increase in cartridge maximum pressure over the .45 ACP and .45 Super. Maximum Average Pressure is: 45 ACP (21,000 PSI), .45 ACP +P (23,000 PSI), .45 Super (28,000 PSI), .460 Rowland (40,000 PSI). The result of this pressure increase is a potential for 185-grain (12.0 g) bullets to achieve 1,500 ft/s (460 m/s) MV and 230-grain (15 g) bullets to achieve 1,340 ft/s (410 m/s). The second element, in regard to M1911 type autoloaders, is to dampen or reduce the velocity of the slide to a manageable level.
M1911 autoloaders converted for this cartridge require a compensator. The increase in slide velocity over a standard .45 ACP, or even a .45 Super round, cannot be properly controlled with an increase in recoil spring rate alone. A conversion requires a compensator to delay unlocking of the M1911 action until pressure has fallen to more manageable levels. Without a compensator, slide or frame failure would result.
Conversion kits co-developed by Wild West Guns and Jonny Rowland for the Smith & Wesson M&P, Glock and Springfield Armory Tactical striker type pistols, due to locking system differences, do not require use of a compensator. Slide velocity in these converted firearms is controlled with a change to the recoil spring alone. Subsequently, the converted firearm is lighter and more compact than a converted 1911 type.
Either type of modified autoloader theoretically can still fire .45 ACP cartridges; however, head spacing would not be at the case mouth, which is the proper location. Instead, the cartridge would be held in position by the gun's extractor. Additionally, the bullet would be unsupported in the forward 1/16" portion of the chamber so accuracy would suffer and high recoil spring rates intended for the .460 Rowland cartridge would prevent reliable cycling. Since the conversion is not permanent, the pistol's owner is free to exchange their .45 ACP and .460 Rowland barrel assemblies.
Pistols and carbines based on a closed-bolt semiautomatic version of the MAC-10 design are available in .460 Rowland.[4]
Some revolvers may be modified for use with the .460 Rowland. Typical examples are the Ruger Blackhawk and Smith & Wesson Model 25/625 that were originally chambered for the .45 ACP. The conversion of revolvers requires deepening the chambers, and is effectively permanent, unless the owner has a replacement cylinder fitted. Dan Wesson also produced for several years a revolver specifically made for the 460 Rowland, which would also chamber .45 ACP, .45 Super and .45 Winchester Magnum (all require moon clips).