Wildcat cartridge

Last updated
.243 Winchester Ackley Improved (left) and .243 Winchester (right) 243 with 243 Ackley.jpg
.243 Winchester Ackley Improved (left) and .243 Winchester (right)

A wildcat cartridge, often shortened to wildcat, is a custom cartridge for which ammunition and/or firearms are not mass-produced. These cartridges are often created in order to optimize a certain performance characteristic (such as the power, size, or efficiency) of an existing commercial cartridge.


Developing and using wildcat cartridges does not generally serve a purpose in military or law enforcement; it is more a hobby for serious shooting, hunting, gunsmithing, and handloading enthusiasts, particularly in the United States. [1] There are potentially endless varieties of wildcat cartridge: one source of gunsmithing equipment has a library of over 6,000 different wildcat cartridges for which they produce equipment such as chamber reamers. [2]

Development of a wildcat

Often, wildcats are commercially sold rounds that have been modified in some way to alter the cartridge's performance. Barrels for the caliber are originally manufactured by gunsmiths specializing in barrel making. Generally, the same makers also offer reloading dies, tools to custom-load bullets into cases. Because changing the barrel of a gun to accommodate custom cartridges requires precision equipment, most wildcats are developed by or in association with custom barrel makers. Ammunition is handloaded, using modified parent cases and the gunsmith-provided wildcat dies. Generally, the supplier of the barrel or dies will also provide the buyer with basic reloading data, giving a variety of powders, charge weights, and bullet weights that can be used for developing loads. Handloaders use the data to develop a load by starting with minimum loads and carefully working up.[ citation needed ]

Wildcat cases and cartridges can be found for sale, but only from small makers. Larger manufacturers usually do not produce wildcats because there is such a limited market for them and because there are no established CIP (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portatives - Permanent International Commission for the Proof of Small Arms) or SAAMI standards, which causes liability concerns.[ citation needed ]

Wildcat goals and methods

From left to right: cross-sectioned and normal .338 Yogi wildcat cartridge cases compared to a factory .338 Lapua Magnum case. 338 YOGI and 338 Lapua Magnum.jpg
From left to right: cross-sectioned and normal .338 Yogi wildcat cartridge cases compared to a factory .338 Lapua Magnum case.

Wildcat cartridges are developed for many reasons. Generally, the goal is to optimize some characteristics of a commercial cartridge in a given context. Higher velocities, greater energy, better efficiency, greater consistency (which yields greater precision), and complying with a minimal permitted caliber or bullet weight for the legal hunting of certain species of game in a particular jurisdiction are the top reasons. The sport of metallic silhouette shooting, has given rise to a great number of wildcats, as several rifle rounds are adapted to fire from a handgun. [3] In using autopistols for hunting or competitive shooting, improved feeding of softnose or hollowpoint bullets is also an issue; the bottlenecked .45/38, for instance, was created because the straight-cased .45 ACP had trouble feeding hollow points. [4]

Wildcat cartridges are generally developed because:

Some methods used to develop a wildcat are:

Example wildcat cartridges

In terms of sheer numbers of varieties, there are more wildcat cartridges than there are production cartridges. Most wildcats are custom made, therefore are not generally well-known. Some wildcat cartridges, however, are produced commercially in small quantities by small manufacturers. This is a list of some representative wildcats.

Wildcat cartridges in Australia

In Australia, wildcat cartridges were relatively common.[ citation needed ] Most are made primarily for hunting species such as deer, kangaroo, and are generally based on the .303 British because of the post-war popularity of that round and of the cheap surplus Australian Lee–Enfield MkIII military rifles available. Many of these surplus rifles were re-barreled to .257 caliber, known as the 303-25. One of the unique features is that these cartridges relied less on handloading - and instead, factory ammunition was produced by the Super Cartridge Company, Riverbrand, IMI, and Sportco.

Since having an existing barrel rebored and rechambered was (at that time) less expensive than fitting a new barrel, a 303-25 rifle with a worn-out barrel could be economically converted to .277 caliber, known as the 303-270.

The .222 Remington - a .222 Rimmed in a Martini was also commonly found. As too were the "Tini-Mite" and "Mini-Mite" cartridges, .17 caliber rimfire cartridges based on the .22 Long Rifle case. [2]

Commercially accepted wildcats

Some cartridges started out as custom-made (non-commercially developed) wildcats and gained wide enough acceptance or popularity to become commercial cartridges. Generally, cartridges become popular commercially after a commercial firearms maker begins offering a weapon chambered in the cartridge. Once popular enough, funding is generated for SAAMI standards development. After SAAMI standards are in place, any firearms or ammunition maker can be sure that any products manufactured to the SAAMI standards can be safely used.

Some examples of custom cartridges that became commercially accepted are:

Commercially developed wildcats

Though a cartridge technically has to not be developed commercially to be considered a wildcat, some commercial cartridges were developed by ammunition and firearm manufacturers by modifying existing cartridges – using essentially the same process used to make wildcats. Cartridges that are modified by being made longer (usually to make them more powerful) are for the most part only created commercially because of the difficulty of the process. One example of such a cartridge is the .357 Magnum, which was developed from the .38 Special in 1934 by firearms manufacturer Smith & Wesson.

Second (and later) generation wildcats

Some wildcats are based not on commercial rounds, but on other successful wildcats. The .308 × 1.5" Barnes, a wildcat from noted cartridge author Frank Barnes made by simply necking a .308 Winchester back to 1.5 inches (38 mm) in length (38.1 mm) is probably the best example of a wildcat that has spawned many other successful wildcats. The .308 x 1.5" case is available from a number of case manufacturers and differs from a homemade .308 x 1.5" in that it has a small primer pocket, whereas the original .308 Winchester case has a larger primer pocket (the smaller primer is more suited to the smaller case capacity of the short round). There are at least 8 wildcats that are made from the small primer .308 x 1.5" brass, including some very successful benchrest rounds, including the Benchrest Remington family of cartridges, .22 BR, 6mm BR, 6.5mm BR, 7mm BR, .30 BR.

Another example is the .220 Russian, based on the 7.62×39mm. Since nearly all 7.62×39mm ammunition made in the 1970s used the complex-to-reload Berdan priming, and often steel cases, it made a poor choice for wildcatting. The .220 Russian, however, was and still is readily available in Boxer-primed, brass cases of high quality. The .220 Russian is still the parent cartridge of choice for the PPC line of cartridges, such as the .22 PPC and 6mm PPC, even though there are far more PPC-chambered firearms available than .220 Russian chamberings. Likewise, the PPC line of cartridges were the parent case of the 6.5 Grendel, a long-range, high-energy cartridge for the AR-15. [23]

See also

Notable wildcat cartridges

Related Research Articles

<span class="mw-page-title-main">Cartridge (firearms)</span> Ammunition consisting of a casing, projectile, propellant, and primer

A cartridge or a round is a type of pre-assembled firearm ammunition packaging a projectile, a propellant substance and an ignition device (primer) within a metallic, paper, or plastic case that is precisely made to fit within the barrel chamber of a breechloading gun, for the practical purpose of convenient transportation and handling during shooting. Although in popular usage the term "bullet" is often informally used to refer to a complete cartridge, it is correctly used only to refer to the projectile.

.357 SIG Pistol cartridge designed by SIG Sauer and Federal Premium Ammunition

The .357 SIG is a bottlenecked rimless centerfire handgun cartridge developed by the Swiss-German firearms manufacturer SIG Sauer, in cooperation with ammunition manufacturer Federal Premium. The cartridge is used by a number of law enforcement agencies.

.454 Casull High power firearm cartridge

The .454 Casull is a firearm cartridge, developed as a wildcat cartridge in 1958 by Dick Casull, Duane Marsh and Jack Fullmer. It was announced in November 1959 by Guns & Ammo magazine. The design is a lengthened and structurally improved .45 Colt case. The wildcat cartridge went mainstream when Freedom Arms brought a single action five-shot revolver chambered in .454 Casull to the retail firearms market in 1983. Ruger followed in 1997, chambering its Super Redhawk in this caliber. Taurus followed with the Raging Bull model in 1998 and the Taurus Raging Judge Magnum in 2010. The .45 Schofield and .45 Colt cartridges can fit into the .454's chambers, but not the other way around because of the lengthened case.

.44 Magnum Revolver cartridge designed by Elmer Keith and Smith & Wesson (S&W)

The .44 Remington Magnum, also known as .44 Magnum or 10.9x33mmR, is a rimmed, large-bore cartridge originally designed for revolvers and quickly adopted for carbines and rifles. Despite the ".44" designation, guns chambered for the .44 Magnum round, and its parent, the .44 Special, use 0.429 in (10.9 mm) diameter bullets. The .44 Magnum is based on the .44 Special case but lengthened and loaded to higher pressures for greater velocity and energy.

The .256 Winchester Magnum is a firearms cartridge developed by Winchester, and was produced by necking-down a .357 Magnum cartridge to .257 diameter. It was designed for shooting small game and varmints.

.300 Whisper

The .300 Whisper is a CIP standard cartridge in the Whisper family, a group of cartridges developed in the early 1990s by J.D. Jones of SSK Industries. It was developed as a multi-purpose cartridge, capable of utilizing relatively lightweight bullets at supersonic velocities as well as heavier bullets at subsonic velocities.

<span class="mw-page-title-main">.30-30 Winchester</span> Rifle cartridge designed by the Winchester Repeating Arms Company

The .30-30 Winchester/.30 Winchester Center Fire cartridge was first marketed in 1895 for the Winchester Model 1894 lever-action rifle. The .30-30, as it is most commonly known, and the .25-35 were offered that year as the United States's first small-bore sporting rifle cartridges designed for smokeless powder. Since its introduction, it has been surpassed by many cartridges in the long-range shooting attributes of speed, energy, and trajectory, yet remains in widespread use because of its practical effectiveness in forested hunting situations.

6mm PPC

The 6mm PPC, or 6 PPC as it is more often called, is a centerfire rifle cartridge used almost exclusively for benchrest shooting. It is one of the most accurate cartridges available at distances of up to 300 meters. This cartridge's accuracy is produced by a combination of its stout posture, being only 31 mm (1.22 in) long, and aggressive shoulder angle of 30 degrees. Its primary use has been benchrest shooting matches since the 1980s.

.222 Remington

The .222 Remington or 5.7×43mm (C.I.P), also known as the triple deuce, triple two, and treble two, is a centerfire rifle cartridge. Introduced in 1950, it was the first commercial rimless .22 (5.56 mm) cartridge made in the United States. As such, it was an entirely new design, without a parent case. The .222 Remington was a popular target cartridge from its introduction until the mid-1970s and still enjoys a reputation for accuracy. It remains a popular vermin or "varmint" cartridge at short and medium ranges with preferred bullet weights of 40–55 grains and muzzle velocities from 3,000 to 3,500 ft/s (915–1,067 m/s).

<span class="mw-page-title-main">.280 Remington</span>

The .280 Remington, also known as the 7mm-06 Remington and 7mm Express Remington, was introduced in 1957 for the Remington model 740, 760, 721, and 725 rifles.

8mm Remington Magnum

The 8mm Remington Magnum belted rifle cartridge was introduced by Remington Arms Company in 1978 as a new chambering for the model 700 BDL rifle. The 8mm Remington Magnum's parent case is the .375 H&H Magnum. It is a very long and powerful cartridge that cannot be used in standard length actions, such as those that accommodate the .30-06 Springfield.

The .260 Remington cartridge was introduced by Remington in 1997. Many wildcat cartridges based on the .308 Winchester case had existed for years before Remington standardized this round.

.22 caliber, or 5.6 mm caliber, refers to a common firearms bore diameter of 0.22 inch (5.6 mm).

.284 Winchester

The .284 Winchester is a cartridge that has enjoyed a resurgence due to interest from long-range competitive shooters. Winchester has continued to produce brass cases for this since 1963. Introduced by Winchester in 1963, the .284 Winchester was designed to achieve .270 Winchester and .280 Remington performance from the new Winchester Model 100 autoloader and Winchester Model 88 lever-action rifles.

The 6×45mm is a rimless, bottlenecked cartridge based on the .223 Remington or 5.56 NATO cartridge necked up to .243 (6mm). The cartridge is also known as the 6mm-223 Remington or 6mm/223.

.30-06 Springfield wildcat cartridges Non-standard rifle cartridge

.30-06 Springfield wildcat cartridges are cartridges developed from a 30-06 Springfield "parent cartridge" through narrowing or widening the cartridge neck to fit a smaller or larger bullet in an attempt to improve performance in specific areas. Such wildcat cartridges are not standardized with recognized small arms standardization bodies like the SAAMI and the CIP.

Varmint rifle

Varmint rifle is an American English term for a small-caliber precision firearm or high-powered airgun primarily used for both varmint hunting and pest control. These tasks include killing three types of pests or nuisance animals that spread diseases or destroy crops or livestock:

.500 S&W Magnum Revolver cartridge designed by Cor-bon and Smith & Wesson (S&W)

The .500 S&W Magnum or 12.7×41mmSR is a .50 caliber semi-rimmed revolver cartridge developed by Cor-Bon in partnership with the Smith & Wesson "X-Gun" engineering team for use in the Smith & Wesson Model 500 X-frame revolver and introduced in February 2003 at the SHOT Show. It has two primary design purposes: as a hunting handgun cartridge capable of taking all North American game species, and to be the most powerful production handgun cartridge to date.

Nosler cartridges

Nosler produces six different hunting cartridges. The first to be introduced was .26 Nosler, followed by .28 Nosler, .30 Nosler, .33 Nosler, .22 Nosler, and .27 Nosler.


  1. "Guns per Capita in the US". Reuters. 2007-08-28. Retrieved 2009-03-03.
  2. 1 2 Frank C. Barnes (2003). Stan Skinner (ed.). Cartridges of the World, 10th Ed. Krause Publications. ISBN   0-87349-605-1.
  3. Robinson, John. "Wildcats". Sporting Shooters’ Association of Australia. Retrieved 1 October 2010.
  4. Barnes, Frank C. Cartridges of the World (Northfield, Illinois: DBI, 19776), p. 140, ".45-38 Auto Pistol".
  5. Case-Forming Top Contender Hunting Loads, Performance Shooter, May 1997; includes information on cold forming and fire forming, including the "Cream of Wheat" fire forming method.
  6. 1 2 Nonte, Jr., George C. (1978). Basic Handloading. USA: Times Mirror Magazines, Inc. ISBN   0943822114. LCCN   77-26482.
  7. ".30 Herrett". Archived from the original on 2007-11-01. Retrieved 2007-11-14.
  8. 1 2 3 "Wildcat Cartridges" . Retrieved 2007-11-14.
  9. ".357 Herrett". Archived from the original on 2007-11-01. Retrieved 2007-11-14.
  10. AmmoGuide.com, free registration may be required.
  11. ".22 Eargesplitten Loudenboomer". RelaodersNest.com.
  12. Ackley, P.O. (1927) [1962]. Handbook for Shooters & Reloaders. vol I (12th Printing ed.). Salt Lake City, Utah: Plaza Publishing. p. 442. ISBN   978-99929-4-881-1.
  13. "The Great .22-250". Rifle Shooter Magazine. Archived from the original on 2012-04-18. Retrieved 2007-11-14.
  14. 1 2 3 "Rifle Cartridges" . Retrieved 2007-11-14.
  15. Cartridges of the World p. 188.
  16. Chuck Hawks. ".454 Casull" . Retrieved 2007-11-14.
  17. ".454 Casull" . Retrieved 2007-11-14.
  18. Barnes, Frank C., ed. by John T. Amber. Cartridges of the World (Northfield, Illinois: DBI Books, 1972), p.67.
  19. John Taffin. "TAFFIN TESTS: THE .38-40 (.38WCF)" . Retrieved 2007-11-14.
  20. Barnes, Frank C., ed. by John T. Amber. Cartridges of the World (Northfield, Illinois: DBI Books, 1972), p.148, ".22 Remington Jet".
  21. "Pistol Cartridges" . Retrieved 2007-11-14.
  22. "The Diminutive 204 Ruger". Ron Spomer Outdoors. Retrieved 2021-06-15.
  23. Chuck Hawks. "The 6 mm PPC-USA" . Retrieved 2007-11-14.