Самодельные патроны для огнестрельного оружия.

Custom cartridge for firearms

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, or may merely be intended as novelty items. 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. 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.

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. 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.

In Australia, wildcat cartridges were relatively common. 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. .22 CHeetah. A .308 BR (Bench Rest) case necked down to .22 caliber, the .22 CHeetah provides a flat trajectory with a .22 caliber bullet that has a relatively high speed of 4,000 ft/s. Hard on barrels, it provides a very effective 300 yard varmint round. .303/25. A .303 British cartridge necked down to fire a .25 caliber projectile, developed in Australia during the 1940s as a Kangaroo culling and pest control round. Popularised in the late 1940s and 1950s in New South Wales, owing to restrictions in that state on ownership of .303 British caliber firearm and the difficulties of obtaining commercial hunting arms and ammunition from overseas. Now largely obsolete, but there are still large numbers of converted Lee–Enfield rifles chambered for this round in Australia.

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. .38 40. One of the oldest wildcats, the .38 40, introduced by Winchester Repeating Arms Company in 1874, was made by necking down a .44 40. Actually a .401 in (10.2 mm) cartridge, the .38 40 had faded into obsolescence before being revived with the growing popularity of Cowboy action shooting. The ballistics of the .38 40 are close to those of the .40 S&W. .221 Fireball. This cartridge was developed by Remington Arms for the XP 100 pistol, which was a single shot bolt action pistol. The .221 Fireball was a necked back .222 Remington, designed for greater efficiency in the 10 in (25 cm) barrel of the XP 100. Even loaded with a smaller load of faster powder for the short barrel, the .221 Fireball lived up to its name, with a massive muzzle flash; the performance, however, was unheard of for its day: over 2700 feet per second (885 m/s) out of the short XP 100 barrel. It remains the fastest SAAMI approved handgun cartridge, and the cartridge is so efficient and accurate that it has been chambered in rifles as well. .22 Remington Jet. This cartridge was developed by Remington for a Smith & Wesson Model 53 revolver and a Marlin Model 62 lever action rifle, but the rifle was never produced in this caliber. The .22 Remington Jet was a necked down .357 Magnum case. The .22 Jet is no longer manufactured by Remington or other commercial manufacturers. .357 SIG. This now popular pistol cartridge was developed by Swiss weapons company Sig Sauer in an attempt to produce ballistics matching the powerful .357 Magnum revolver load, but in a semi automatic pistol cartridge. The cartridge was made by necking down and slightly stretching the .40 S&W case, which itself derived from the 10mm Auto. .400 Corbon. This cartridge was designed to produce 10mm Auto ballistics in a cartridge that could be chambered in a .45 ACP pistol with a simple barrel swap. It was made by necking a .45 ACP down to .40 (10 mm). Initially, no firearms were available in .400 Cor Bon, but barrels in the new caliber were produced for the M1911 pistol. .41 Action Express. Developed in 1986 by Action Arms for the Jericho 941 pistol. It, like the .357 SIG, attempted to make a magnum power cartridge for a semi automatic pistol. It started with a .41 Magnum case and cut it down to fit in a semi automatic pistol chambered for 9×19mm. The rim was then turned down to the same dimensions as the 9×19mm, making it a rebated rim cartridge. This allowed a unique switch up to a larger caliber. The .41 AE never saw huge commercial success because of the creation of the similarly powerful .40 S&W in 1990. .204 Ruger. Introduced in 2004 by Ruger, in its time it held the title of fastest production cartridge with a velocity of 4225 ft/s (1290 m/s) with a , .204 bullet from a barrel. Intended as a varmint rifle cartridge, the .204 was based on the .222 Remington Magnum, which is slightly longer than the .223 Remington and offers about 5% more case capacity. Designed to have a very long point blank range, the factory loading offers impressive ballistics, placing a 32gr Hornady V Max bullet 1.96 inches high at , and low at .

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 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.