.300 Whisper
Encyclopedia
The .300 Whisper is a wildcat 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 (200–250 grains) at subsonic
velocities.
The .300 Whisper was originally based on the .221 Fireball case necked up to .30 caliber. However, avid reloaders have found the .223 Remington
or 5.56×45 mm NATO
works well when shortened and resized to .30 caliber. Firing in the .300 Whisper chamber results in a slightly sharper shoulder. Magnum
pistol powders such as H110 work well for subsonic loads. Sierra 240 grain (16 g) jacketed bullets work well if the barrel
has a 1:8 twist
. Barrels with a 1:10 twist will stabilize 220 grain (14 g) bullets at subsonic speeds. 125 grain (8 g) bullets will reach 2400 ft/s (730 m/s).
There are a few points to be considered regarding the utility of the .300 Whisper:
In addition to special applications in suppressed firearms, the .300 Whisper has become popular with metallic silhouette
shooters due to its low recoil, good long range performance, and very high accuracy.
of SSK Industries. In order to sidestep this branding (and/or any licensing fees required to use the "Whisper" name legally), other manufacturers tend to use different names for the same cartridge, such as ".300 warrior carbine", ".300 Fireball" or ".300-221", both based on the .221 Fireball parent case.
Wildcat cartridge
A wildcat cartridge, or wildcat, is a custom cartridge for which ammunition and firearms are not mass produced. These cartridges are often created in order to optimize a certain performance characteristic of an existing commercial cartridge.Developing and using wildcat cartridges does not...
in the Whisper family
Whisper Family of Firearm Cartridges
The Whisper family of firearm cartridges is a group of wildcat cartridges developed in the early 1990s by J.D. Jones of SSK Industries. The Whisper Family was developed as a line of accurate, multi-purpose cartridges using relatively heavy rifle bullets for a given caliber in subsonic loads...
, a group of cartridges
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
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
Supersonic
Supersonic speed is a rate of travel of an object that exceeds the speed of sound . For objects traveling in dry air of a temperature of 20 °C this speed is approximately 343 m/s, 1,125 ft/s, 768 mph or 1,235 km/h. Speeds greater than five times the speed of sound are often...
velocities as well as heavier bullets (200–250 grains) at subsonic
Speed of sound
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at , the speed of sound is . This is , or about one kilometer in three seconds or approximately one mile in five seconds....
velocities.
The .300 Whisper was originally based on the .221 Fireball case necked up to .30 caliber. However, avid reloaders have found the .223 Remington
.223 Remington
The .223 Remington is a sporting cartridge with almost the same external dimensions as the 5.56×45mm NATO military cartridge. The name is commonly pronounced either two-two-three or two-twenty-three. It is loaded with a diameter, jacketed bullet, with weights ranging from , though the most common...
or 5.56×45 mm NATO
5.56x45mm NATO
5.56×45mm NATO is a rifle cartridge developed in the United States and originally chambered in the M16 rifle. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries. It is derived from, but not identical to, the .223 Remington cartridge...
works well when shortened and resized to .30 caliber. Firing in the .300 Whisper chamber results in a slightly sharper shoulder. Magnum
Magnum
Magnum may refer to several things:* Moses Magnum, a Marvel Comics villain*Magnum, P.I., a television series** Thomas Magnum, the lead character...
pistol powders such as H110 work well for subsonic loads. Sierra 240 grain (16 g) jacketed bullets work well if the barrel
Gun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....
has a 1:8 twist
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...
. Barrels with a 1:10 twist will stabilize 220 grain (14 g) bullets at subsonic speeds. 125 grain (8 g) bullets will reach 2400 ft/s (730 m/s).
There are a few points to be considered regarding the utility of the .300 Whisper:
- Supersonic loads are capable of matching ballistics of the 7.62x39mm and the .30-30 Winchester.30-30 WinchesterThe .30-30 Winchester/.30 Winchester Center Fire/7.62×51mmR cartridge was first marketed in early 1895 for the Winchester Model 1894 lever-action rifle. The .30-30 , as it is most commonly known, was the USA's first small-bore, sporting rifle cartridge designed for smokeless powder. The .30-30 is...
, making the .300 Whisper very capable as a short range deer hunting cartridge. - The use of heavy bullets, along with the low powder weight and small case capacity, make the .300 Whisper ideal for use with sound suppressorSuppressorA suppressor, sound suppressor, sound moderator, or silencer, is a device attached to or part of the barrel of a firearm which reduces the amount of noise and flash generated by firing the weapon....
s. These subsonic loads offer energy levels similar to that of the popular .45 ACP.45 ACPThe .45 ACP , also known as the .45 Auto by C.I.P., is a cartridge designed by John Browning in 1904, for use in his prototype Colt semi-automatic .45 pistol and eventually the M1911 pistol adopted by the United States Army in 1911.-Design and history:The U.S...
pistol cartridge, but range is substantially increased due to the longer, more efficient .30 caliber bullet. - Cases for the .300 Whisper can be formed from common and plentiful .223 Remington brass by sizing and trimming to length. However, J.D. Jones has recommended against this, citing the difference in case thickness at the neck (compared to the .221 Fireball) as a potential issue. This problem can be exacerbated when military 5.56x45mm cases are used. (The Whisper name is trademarked thus: the only firearms with a .300 Whisper chamber are those from J.D. Jones and Thompson CenterThompson Center ArmsThompson/Center Arms Company is an American firearms company based in Rochester, New Hampshire. The company is best known for its line of interchangeable barrel single-shot pistols and rifles. Thompson Center manufactures muzzleloading rifles and is credited with creating the resurgence of their...
, which licensed the name. All other guns are cut to .300/221 which has different chamber specifications than the Whisper, particularly in neck wall thickness. Because the .300 Whisper is a wildcat cartridge there were no established Sporting Arms and Ammunition Manufacturers' InstituteSporting Arms and Ammunition Manufacturers' InstituteThe Sporting Arms and Ammunition Manufacturers' Institute is an association of American firearms and ammunition manufacturers...
(SAAMI) specifications for the chamber reamers, and the necks were cut to allow for standard .308 neck thickness, which is approximately the same thickness as produced from forming .223 brass. Typically only guns with Whisper chambers will have problems with .223 brass—.300/221 chambers work very well with .223 brass, and the .223 brass is considerably stronger than .221 brass.) - Perhaps most importantly, any firearmFirearmA firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...
with a .223 Remington bolt face can be converted to .300 Whisper by re-barreling the action. As such, the .300 Whisper works well in AR-15AR-15The AR-15 is a lightweight, 5.56 mm, air-cooled, gas-operated, magazine-fed semi-automatic rifle, with a rotating-lock bolt, actuated by direct impingement gas operation. It is manufactured with the extensive use of aluminum alloys and synthetic materials....
–based rifles, especially when some type of gas regulator is installed.
In addition to special applications in suppressed firearms, the .300 Whisper has become popular with metallic silhouette
Metallic silhouette
Metallic silhouette shooting is a group of target shooting disciplines that involves shooting at metal cutouts representing game animals at varying distances. Metallic silhouette shooting can be done with airguns, black powder firearms, modern handguns, or modern rifles...
shooters due to its low recoil, good long range performance, and very high accuracy.
Trademark
"Whisper" is a registered trademarkTrademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...
of SSK Industries. In order to sidestep this branding (and/or any licensing fees required to use the "Whisper" name legally), other manufacturers tend to use different names for the same cartridge, such as ".300 warrior carbine", ".300 Fireball" or ".300-221", both based on the .221 Fireball parent case.
See also
- List of rifle cartridges
- 300 AAC Blackout (7.62x35mm)300 AAC Blackout (7.62x35mm)300 AAC Blackout , SAAMI short name "300 BLK" is a rifle cartridge developed in the United States and originally chambered in the M4 rifle.-History:...
- .30 HRT
- .338 Spectre
- .458 SOCOM.458 SOCOMThe .458 SOCOM is a relatively large round designed for a specialized upper receiver that can be mounted on any AR-15 pattern rifle. The round offers a muzzle velocity and .- History:...
- .450 Bushmaster.450 BushmasterThe .450 Bushmaster is a rifle cartridge developed by Tim LeGendre of LeMag Firearms LLC, and licensed to Bushmaster Firearms International for production and distribution. LeGendre still retains ownership of the concept...
- .50 Beowulf.50 BeowulfThe .50 Beowulf [12.7×42 mm Rb] is a rifle cartridge developed by Alexander Arms for use in a modified AR-15 rifle. The cartridge utilizes a rebated rim, sized to match the rim of the 7.62×39mm and 6.5 mm Grendel rounds...
- .50 Hush Puppy