John Linebaugh

John Linebaugh is an American gunsmith from Cody, Wyoming, known for creating custom firearms. He is inventor of the .500 Linebaugh (invented 1986) and .475 Linebaugh (1988) cartridges. Gunwriter John Taffin, a big-bore enthusiast, describes Linebaugh as a "pioneer" in developing powerful sixguns.

Linebaugh's early efforts in the 1970s produced revolvers made to handle much more powerful loadings of .45 Colt than standard firearms, an later expanded into creating his own cartridge designs. After inventing the .500 and .475 Linebaugh, he later lengthened created a variant of each cartridge, lengthened to 1.6 inches, and appended "Maximum" to their names. Linebaugh focused on developing cartridges which were compatible with standard-size revolvers, keeping them "old school" or "packable" rather than oversize.

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Further reading

.475 Linebaugh

The .475 Linebaugh is an extremely potent rimmed revolver cartridge developed by John Linebaugh in the late 1980s. The cartridge is based on the .45-70 Government case cut down to 1.5 inches and loaded with .475-inch-diameter (12.1 mm) bullets weighing from 320 grains (21 g) to 440 grains (29 g). Although the .45 Silhouette cartridge is also derived from a .45-70 trimmed down to 1.5 inches, the .475 Linebaugh saw the same case modified to accept .475 caliber bullets, resulting in significantly different ballistic performance.

The then-new .475 Linebaugh was first announced in the May 1988 issue of Guns & Ammo in an article written by Ross Seyfried.

Usage

The .475 Linebaugh is primarily intended for hunting big game or as a backup when confronting dangerous animals. A 370-grain (24 g) bullet starting out at 1,495 feet per second (456 m/s) develops 1,840 foot-pounds force (2,490 J) of energy, and a 440-grain (29 g) bullet at 1,360 feet per second (410 m/s) develops 1,800 foot-pounds force (2,400 J). In comparison to another popular magnum revolver cartridge, the .454 Casull, the Casull's 300-grain (19 g) .454 caliber bullet at 1,650 feet per second (500 m/s) and 1,800 foot-pounds force (2,400 J) of energy is surpassed with the Linebaugh's loading of a 370-grain (24 g) .475 caliber bullet at 1,495 feet per second (456 m/s) and 1,840 foot-pounds force (2,490 J) of energy. Both the .475 Linebaugh and the .454 Casull are ballistically similar and both can also be loaded to higher pressures but the .475 Linebaugh still has an edge on the latter.

.500 Linebaugh

The .500 Linebaugh is a .50 caliber handgun cartridge designed for use in revolvers. It is considered one of the most powerful handgun cartridges designed in terms of kinetic energy and power factor (momentum).

History

The .500 Linebaugh cartridge was designed by John Linebaugh of Maryville, Missouri, in 1986. John Linebaugh had been converting .45 Colt six-shooters to five-shot revolvers, thus offering a stronger cylinder which could withstand the firing of higher-pressure .45 Colt ammunition. While this venture was successful, he continued to search for a more powerful cartridge, which resulted in the .500 Linebaugh.

The cartridge case itself was designed by cutting off the .348 Winchester case to 1.405 in (35.7 mm), turning the rim to a diameter of .610 in (15.5 mm) and opening the case mouth to accept a .510 caliber (12.9 mm) bullet. The first revolvers converted to use the .500 Linebaugh were the Ruger Bisley and the Seville revolvers. Due to the demise of the Seville revolvers in the early 1990s, all subsequent conversions have been carried out on revolvers based on the Ruger Bisley frame.