CheyTac Intervention
Encyclopedia
The CheyTac Intervention is an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 bolt action sniper rifle
Sniper rifle
In military and law enforcement terminology, a sniper rifle is a precision-rifle used to ensure more accurate placement of bullets at longer ranges than other small arms. A typical sniper rifle is built for optimal levels of accuracy, fitted with a telescopic sight and chambered for a military...

 manufactured by CheyTac LLC for long range soft target
Soft target
Soft target is a military term referring to unarmored/undefended targets needing to be destroyed. For example, a soft target would be an automobile, a house, or assembly of people while a hard target could be a main battle tank or a well defended installation...

 interdiction. It is fed by a detachable single stack magazine, which holds 7 rounds. It fires .408 CheyTac or .375 CheyTac ammunition. CheyTac papers state that the entire system is capable of delivering sub-MOA
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....

 accuracy at ranges of up to 2,500 yards (2,300 m), one of the longest ranges of all modern-day sniper rifles. It is based on the EDM Arms Windrunner
EDM Arms Windrunner
The Windrunner M96 is a bolt-action, magazine-fed rifle designed by American firearms designer William Ritchie and manufactured by his company, EDM Arms. It is chambered for .50 BMG, and a variant designated the M98 is chambered for .338 Lapua Magnum. It was designed to be able to be broken down in...

.

Cartridge, bullets and barrels

CheyTac L.L.C researched the optimum cartridge case, bullet and barrel configuration for very long range use. For this the .408 Chey Tac
.408 Chey Tac
The .408 Cheyenne Tactical is a specialized rimless, bottlenecked, centerfire cartridge for military long-range sniper rifles that was developed by Dr. John D. Taylor and machinist William O. Wordman...

 cartridge was developed that fires very-low-drag mono metal bullets that were specially designed for the Long Range Rifle System by the now (2010) defunct company, Lost River Ballistic Technologies.

Lost River Ballistic Technologies inventor, Mr. Warren Jensen, stated that "the .408 Chey Tac was the first bullet/rifle system that utilizes a balanced flight projectile. To achieve balanced flight the linear drag has to be balanced with the rotational drag to keep the very fine nose (meplat) of the bullet pointed directly into the oncoming air. It should result in very little precession and yaw at extreme range and allows accurate flight back through the transonic
Transonic
Transonic speed is an aeronautics term referring to the condition of flight in which a range of velocities of airflow exist surrounding and flowing past an air vehicle or an airfoil that are concurrently below, at, and above the speed of sound in the range of Mach 0.8 to 1.2, i.e. 600–900 mph...

 region. This is hard to achieve for small arms projectiles. Mathematically you are at a great disadvantage trying to achieve balanced flight with a lead core non mono metal bullet. The rotational mass/surface area ratio is too high."

The balanced flight projectile patent can be found at the US Patent Office, Controlled spin projectile, . According to the patent, a projectile engraved and launched according to the specifications of the patented invention should decelerate from 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...

 flight through transonic
Transonic
Transonic speed is an aeronautics term referring to the condition of flight in which a range of velocities of airflow exist surrounding and flowing past an air vehicle or an airfoil that are concurrently below, at, and above the speed of sound in the range of Mach 0.8 to 1.2, i.e. 600–900 mph...

 to 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....

 in a stable and predictable manner effective to a range beyond 3,000 yards (2,743 m). It implies that, amongst several other preconditions, the rifle barrel has to have specific rifling
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...

 dimensions to achieve a desired amount of axial air drag on the bullet's surface, which reduces the bullet's spinrate to achieve balanced flight.

To achieve balanced flight the rifling
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...

 twist rate for the .408 CheyTac chambering was chosen at 330.2 mm (1 in 13 in), with eight 0.4080 in diameter grooves, 0.4010 in diameter bore and a 0.050" land width, square cut, with no taper. The later .375 CheyTac round, developed from the .408 CheyTac, uses a 292 mm (1:11.5 in) rifling twist rate.

Muzzle brake and suppressor

The .408 CheyTac's light recoil is attributed to the McArthur PGRS-1 muzzle brake that was designed by gunsmith and firearm inventor, Bruce McArthur, owner of The Flint & Frizzen Gun Shop in Clarkston, Michigan. McArthur designed it to strip gases from the projectile before it leaves the muzzle brake.

The CheyTac muzzle brake suppressor
Suppressor
A 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....

, manufactured by OPS INC, is a stainless steel suppressor. The all stainless steel construction with no replaceable parts guarantees a suppressor life that equals or exceeds the life of the rifle. When totally filled with water, the suppressor can be drained in 6 seconds which allows use when emerging from water. If the operator chooses to switch to the muzzle brake, a repeatable 6 minute of arc
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....

 zero change for elevation is required.

Day and night optical sight systems

There are two different day optical sights available. The primary sight is the Nightforce NXS 5.5-22x56 variable magnification telescopic sight
Telescopic sight
A telescopic sight, commonly called a scope, is a sighting device that is based on an optical refracting telescope. They are equipped with some form of graphic image pattern mounted in an optically appropriate position in their optical system to give an accurate aiming point...

 with a 56 mm objective. The alternate sight is the US Optics SN-9. The night vision system chosen is the AN/PVS-14 GEN III Pinnacle monocular. The PVS-14 is attached to the day optic using the Monoloc device. An AN/PEQ-2 infrared laser is used for system support with the night vision sight under conditions where there is insufficient ambient light or the IR laser is needed for further target illumination. The device is attached to a titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 strut.

Meteorological and environmental sensor package

The KESTREL 4000 or 4500 (NV) meteorological and environmental sensor package is used to measure the wind, air temperature, and air pressure. It also collects relative humidity, wind chill, and dew point. All of these points of data are fed directly into the tactical computer so that no manual input is necessary. The KESTREL 4500 NV model has the capability to be used with night vision devices.

Laser rangefinder

A Vector IV mil spec laser rangefinder is used to establish ranging data. This laser rangefinder can measure distance up to 6 km (3.7 mi), angles and also features a 360° digital compass and class 1 eye safe filters. The acquired data can be fed directly into the tactical computer. High end laser rangefinders that can very accurately measure distances over 2,000 m (2,200 yd) are prohibitively expensive for most civilian long-range shooters.

Advanced Ballistic Computer

The CheyTac Advanced Ballistic Computer (ABC) System software package was developed to enhance the long range predictive capabilities of a sniper’s handheld computer. According to the developers the softwares predictive capabilities are based on actual bullet flight data derived from test sessions on the high speed Weibel 1000e Doppler Radar
Doppler radar
A Doppler radar is a specialized radar that makes use of the Doppler effect to produce velocity data about objects at a distance. It does this by beaming a microwave signal towards a desired target and listening for its reflection, then analyzing how the frequency of the returned signal has been...

 at the U.S. Army Proving Grounds, Yuma Arizona. Engineers created algorithms that utilize both known mathematical ballistic models as well as test specific, tabular data in unison.

The system is said to provide the operator with a simple elevation and windage solution through complete integration of external environment, operator, and gun system specifications, enabling small arms weapons operators to produce highly accurate long-range trajectories to any number of specified targets at extreme ranges.

The software package is said to operate on a variety of consumer, hardened and mil-spec R-PDAs running the Windows Mobile 2003 operating system, using inputs from the Kestrel handheld weather station and Vector IV laser rangefinder binoculars.

However, much like other ballistic prediction software, when rounds are used for which no Doppler Radar-established bullet flight data is known, the ABC System relies solely on mathematical ballistic models like all other ballistic prediction computer programs.

Data tables

Data tables in print are provided in the event the tactical ballistic computer fails or the batteries for the device fail. Without computer support the effectiveness of some long-range shooters could be severely reduced, since they may rely heavily on computer support to obtain correct ballistic solutions.

Records

The Intervention holds the world record for best group at a distance, landing 3 bullets within 16⅝ inches (42 cm) at 2,321 yards (2,122 m) near Arco
Arco, Idaho
Arco is a city in Butte County, Idaho, United States. The population was 995 at the 2010 census. The city is the county seat of Butte County.Craters of the Moon National Monument is located along U.S. Route 20, southwest of the city. The Idaho National Laboratory is located east of Arco...

 in Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

http://uktactical.webs.com/408cheytachunter.htm.

On the Discovery Channel TV show Future Weapons
Future Weapons
Future Weapons, sometimes also written as FutureWeapons and Futureweapons, is a documentary television series that premiered on April 19, 2006 on the Discovery Channel. Host Richard "Mack" Machowicz, a former Navy SEAL, reviews and demonstrates the latest modern weaponry and military technology...

 April 9, 2007 episode "Massive Attack" the host Richard Machowicz
Richard Machowicz
Richard "Mack" Machowicz, a former Navy SEAL, was the host of the Discovery Channel and Military Channel show Future Weapons. According to the program's introduction, he spent ten years as a U.S. Navy SEAL and now searches for new weapons and military technologies used in modern warfare. He is also...

, a former United States Navy SEAL, made 3 out of 6 shots hit a human sized sheet of metal at a distance of 2,530 yards (2,313 m) at Arco Pass in Idaho.

Accuracy

CheyTac asserts in its Information Paper of 13 November 2006 that "the CheyTac LRRS is a solid anti-personnel system to 2,000 yards (1,830 m). The primary intent of the .408 is as an extreme range anti-personnel system. Groups of 7–9 inches (18–23 cm) at 1,000 yards (914 m), 10 inches (25 cm) at 1500 yards (1372 m) and 15 inches (38 cm) at 2,000 yards (1,829 m) have been consistently obtained.

Groups of 19 inches (48 cm) at 2,100 yards (1,920 m) and 29 inches (74 cm) at 2,400 yards (2,195 m) have also been obtained. All groups that are up to 3,000 yards (2,743 m) are less than 1 minute of angle
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....

for vertical dispersion.

Versions

The CheyTac Intervention comes in several variants:
  • M-200 (29 in (737 mm) barrel length)
  • M-200 Carbine (Now out of production)
  • M-310 (Single shot and repeater sub-variants all with 29 in (737 mm) barrel length)
  • M-325 (Single shot, repeater and tactical sub-variants all with 28 in (711 mm) barrel length)


The main capability differences between the different versions are governed by barrel length which determines the obtainable muzzle velocity. Higher muzzle velocity will extend the effective range of a rifle, everything else being equal. Also, the M-200 and the M-200 Carbine comes with a detachable box magazine and a telescopic stock, whilst the other variants are built on a glass-fiber fixed McMillan stock.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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