A wildcat cartridge, often shortened to wildcat, is a custom-made cartridge for which ammunition and/or firearms are not mass-produced. These cartridges are often created as experimental variants to optimize a certain ballistic performance characteristic of an existing commercial cartridge, or may merely be intended as novelty items.
The .243 Winchester (6×52mm) is a popular sporting rifle cartridge. Developed as a versatile short action cartridge to hunt both medium game and small game alike, it "took whitetail hunting by storm" when introduced in 1955, and remains one of the most popular whitetail deer cartridges. It is also commonly used for harvesting blacktail deer, pronghorns and mule deer with heavier rounds, and is equally suited to varmint hunting with lighter rounds. The .243 is based on a necked down .308 Winchester, introduced only three years earlier. Expanding monolithic copper bullets of approximately 80 to 85 grains or traditional lead rounds of 90 to 105 grains with controlled expansion designs are best suited for hunting medium game, while lighter rounds are intended for varmints.
Benchrest shooting is a shooting sport discipline in which high-precision rifles are rested on a table or bench – rather than being carried in the shooter's hands – while shooting at paper or steel targets, hence the name "benchrest". Both the forearm and buttstock of such a rifle are usually fully supported by bean bags, a bipod/monopod (front/rear) combination, and/or a specially designed fixture device called shooting rest, so that the gun can remain stably pointing at the target without needing to be held by someone. When shooting, the shooter simply sits/stands comfortably behind the table/bench, operates the action and pulls the trigger, without needing to worry about carrying any weight of the gun. This is in contrast to other shooting disciplines, where the shooter has to bear at least part of the gun's weight while holding it steady to aim, even when using support devices such as bipods, tripods or shooting sticks.
The 7mm-08 Remington is a rifle cartridge that is almost a direct copy of a wildcat cartridge developed around 1958 known as the 7mm/308. As these names would suggest, it is the .308 Winchester case necked down to accept 7 mm (.284) bullets with a small increase in case length. Of cartridges based upon the .308, it is the second most popular behind only the .243 Winchester. However, the .308 is more popular than both. In 1980, the Remington Arms company popularized the cartridge by applying its own name and offering it as a chambering for their Model 788 and Model 700 rifles, along with a limited-run series within their Model 7600 pump-action rifles during the early 2000s.
The .204 Ruger / 5.2x47mm is a centerfire rifle cartridge developed by Hornady and Ruger. At the time of its introduction in 2004, the .204 Ruger was the second-highest velocity commercially produced ammunition and the only centerfire cartridge produced commercially for bullets of .204 inch/5 mm caliber.
The 6mm PPC, or 6x38 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.
6mm XC / 6.17x48mm is a rifle cartridge, similar to the 6x47mm Swiss Match.
The 6mm Remington rifle cartridge, originally introduced in 1955 by Remington Arms Company as the .244 Remington, is based on a necked down .257 Roberts cartridge using a .24/6mm bullet. Known for a combination of high velocity, long range, flat trajectory, and accuracy, it is suitable as a dual use hunting cartridge for both medium-sized big game and varmints. When used in the less common earlier slow twist barrels, it offers exceptional range for varmint applications. While not as commercially popular today as the .243 Winchester, the 6mm Remington enjoys a slight ballistic advantage and continues to be popular with handloaders and custom rifle builders.
The .224 Weatherby Magnum (5.56×49mmB) is a sporting cartridge that was developed in the 1940s by Roy Weatherby, and commercial ammunition was produced starting in 1963. At the time it was the only belted magnum varmint cartridge. It is a proprietary cartridge with no major firearms manufacturers chambering rifles for it other than Weatherby. It was originally called the .224 Weatherby Varmintmaster when it was introduced alongside the Weatherby Varmintmaster rifle, but the rifle was discontinued in 1994 and the cartridge was renamed.
The 6.5×47mm Lapua is a smokeless powder rimless bottlenecked rifle cartridge that was developed specifically for 300–1,000 m (328–1,094 yd) competition shooting by ammunition maker Nammo Lapua and the Swiss rifle manufacturer Grünig & Elmiger AG in 2005. Other common names for this cartridge include 6.5×47mm.
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, refers to a common firearms bore diameter of 0.22 inch (5.6 mm) in both rimfire and centerfire cartridges.
The .284 Winchester (7.21x55mmRB) is a rebated rim firearm cartridge, introduced by Winchester in 1963.
The 6.5mm Creedmoor (6.5×48mm), designated 6.5 Creedmoor by SAAMI, 6,5 Creedmoor by the C.I.P. is a centerfire rifle cartridge introduced by Hornady in 2007. It was developed by Hornady senior ballistics scientist Dave Emary in partnership with Dennis DeMille, the vice-president of product development at Creedmoor Sports, hence the name. The cartridge is a necked-down modification of the .30 Thompson Center.
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.
A varmint rifle or varminter is a type of small-caliber, precision-oriented long gun primarily used for varmint hunting and pest control. Such rifles are typically characterized by sniper rifle-like designs such as heavy free-floating barrel, enhanced bedding, ergonomic gunstock, the use of bipod/beanbag and high-power telescopic sight, and the choice of high-muzzle velocity, high-ballistic coefficient munitions, which are all accurizing features of needed for improving repeated shooting, often over long distances.
The 7mm BR Remington / 7.2x38mm, commonly called the 7mm BR or the 7mm Benchrest Remington in long form, was an intermediate cartridge developed by Remington for the Remington XP-100 single-shot bolt-action handgun. The cartridge was developed for the Unlimited Class in the sport of Metallic silhouette shooting. Later it was introduced in the Remington Model XB-40 single-shot bolt-action rifle, which was specifically designed for the benchrest shooting community.
The .20 BR is a centerfire wildcat rifle cartridge. It is based on the .22 BR Remington case necked down to accept a 5.2 millimetres (0.204 in) diameter bullet and maintaining the shoulder angle of 30° and case length of 39 millimetres (1.535 in). The cartridge features a short fat case which is reputed to be both efficient and accurate.
The .308×1.5" Barnes is a wildcat cartridge based on the .308 Winchester. The cartridge is similar to the 7.62×39mm Russian (M43) cartridge though it outperforms the Soviet cartridge. It was designed by Frank C. Barnes in March 1961 by shortening the .308 Winchester to 1.5 in (38 mm) and giving it a shoulder angle of 20° (α=40°) similar to the parent cartridge.
