338 Spectre

The 338 Spectre cartridge is a proprietary round developed specifically for the M4/AR-15 family of gas operated, detachable-box magazine-fed firearms. This cartridge is intended to fill the gap between traditional pistol caliber cartridges and existing intermediate powered rifle cartridges such as 5.56 NATO.

This round was designed so it would use a standard M4/AR-15 lower receiver with only the need to change out the upper receiver. It was carefully designed to stay within the overall length of a cartridge intended for an M4/AR as well as remaining within the safe limits of pressure.

History of .338 Spectre

Marty ter Weeme of Teppo Jutsu invented and developed the 338 Spectre as a dual purpose round, much like his 458 SOCOM round. The parent case is that of a 10mm Magnum, which is a lengthened 10mm case and should not be confused with the shorter round. The case is necked down to accept a .338"-diameter bullet and this in turn offers quite an array of projectiles for the reloader and shooter.

Early prototypes and development of upper receivers used integral suppressors for sniper security teams and other clandestine operations. This was easily accomplished because of the low gas volume generated by the 338 Spectre which makes it an ideal cartridge for use with suppressors.

What it's good for

This extremely versatile round is useful in many situations from law-enforcement and military scenarios to hunting medium-sized game at close distance to casual or professional level target shooting applications. In many ways, this round is superior to the 300 Blackout.

Firearms and Applications

As previously stated, the 338 Spectre was intended for use in the M4/AR-15 platform. It only differs from a standard AR chambered in 5.56 by using a different barrel and bolt.

The case head shares the same dimensions as the 6.8 SPC rifle cartridge. This allows a factory 6.8 SPC rifle bolt to be used in the building of a rifle, carbine or pistol. Likewise, 6.8 SPC rifle magazines will hold a full payload of cartridges as opposed to 5.56 NATO magazines which will hold a reduced amount AR magazines intended for 7.62 x 39mm will hold the full number of rounds intended as well.

For the subsonic loading, a 9mm pistol suppressor will suffice to keep it quiet. Suppressors such as this are much cheaper than the heavy duty suppressors intended for 338 Lapua Magnum.

Not to be confined to the AR platform, the 338 Spectre can be chambered in single shot rifles and pistols as well as bolt-action rifles.

Hunting

For sportsmen and target shooters, the 338 Spectre shines as a cartridge with light recoil and excellent performance on medium size game at close range. Its wide range of projectiles are very appealing to professional shooters as well as recreational sportsmen.

338 Spectre is becoming increasingly popular as a round for close range hog hunting due to its low recoil, accuracy and terminal ballistics. It can also fill this role as a deer or black bear harvester as long as the hunter understands the range limitations of the cartridge.

Law-enforcement

For the law enforcement and military professional, 338 Spectre offers solid and impressive terminal ballistics from what has to be the most-widely used weapons platforms in the United States. It makes for an ideal suppressed round for security elements on sniper teams.

In the LEA/MIL family, AP, and frangible projectiles are available for use in tactical applications.

The AP version of the 338 Spectre configured in a short compact M4, makes for similar tactical applications and performance to the Russian 9x39mm, but utilizing the much more versatile M4 platform.

Target shooting

The inherent accuracy and low recoil of the 338 Spectre has not gone unnoticed by target shooters. Its ballistic performance has been favorably compared with venerable hunting and target cartridges including 357 Maximum, 357 Herrett, 35 Remington and the faster loads using lighter bullets for the 44 Remington Magnum such as the 180-grain loading. 

SBR Ammunition makes a variety of factory 338 Spectre ammunition in Brunswick, Georgia and has been called the authority on this cartridge. SBR also provides quality reloading components including pre-formed brass with a thicker wall construction as opposed to a necked-doen 10mm Magnum case. Furthermore, SBR offers custom reloading dies so shooters and handloaders can make their own ammunition correctly. Rifle and pistol-length barrels chambered in 338 Spectre are also available from SBR. This is pretty much a one-stop shop for all your shooting and reloading needs with regard to 338 Spectre.