The .458 SOCOM (11.63×40mm) is a moderately large round designed to work in an AR-15 platform. This is achieved by installing a 458 bolt and barrel. The 300-grain (19 g) round offers a supersonic muzzle velocity of 1,900 ft/s (580 m/s) and 2,405 ft⋅lbf (3,261 J),[1] similar to a light .45-70 but with a much smaller case.
Prompted by the lack of power offered by the 5.56 NATO cartridge used in the M4 carbine and the M16 rifle, the .458 SOCOM came about from informal discussion of members of the special operationscommand, specifically Task Force Ranger's experience that multiple shots were required to incapacitate members of the opposing force in Mogadishu during Operation Gothic Serpent. Marty ter Weeme of Teppo Jutsu and Tony Rumore of Tromix designed the cartridge in 2000 and Tromix was contracted to build the first .458 SOCOM rifle in February 2001.
The project sponsor set forth a number of specific requirements namely that the cartridge had to fit in the M4 carbine and be capable of firing heavy-for-caliber projectiles at subsonic velocity using suppressors. During the development phase, various other cartridges were considered and proposed to the project sponsor, but rejected as not meeting all the requirements. The cartridges considered were 7.62×39mm, 9×39mm Grom, .45 Professional (which has since become the .450 Bushmaster), and .50 Action Express. At the time, the .499 LWR cartridge was still in the development phase and had not been chambered commercially.
The .45 Professional was ruled out because, in an interview with industry press, the developer of said cartridge stated that steel proprietary to General Motors was used in the bolts and extractor to withstand the high operating pressures. The .50 AE and .499 LWR were ruled out because in 2000 only two bullets were offered in .501 diameter, both developed as pistol bullets for the .50 AE and not heavy enough for the subsonic suppressed role. Research had indicated that a short belted cartridge called the .458 × 1.5" Barnes had been adopted for use in suppressed bolt-action rifles for use in South East Asia during the Vietnam War. It was shown as effective in terms of ballistics, firing a 500-grain bullet subsonically, but not ideally suited for its role due to the size and weight of the platform. Combined with the wide selection of bullets available in .458 diameter, this cemented the choice of caliber.
The cartridge case design was finalized based on discussions with Tony Rumore at Tromix suggesting a lengthened .50 AE case would work well in the magazines as well as be the largest diameter case to be able to feed through the barrel extension. The initial prototype brass still bore the .50 AE head stamp and this has caused some confusion, as the SOCOM case is longer with a narrower rim. The .50 AE rim diameter was reduced from .514 inch to .473 inch for compatibility with other platforms, primarily bolt-action rifles. The .473-inch/12mm-diameter rim was designed in 1888 for the German Commission Rifle chambered in 7.92×57mm Mauser cartridge, and is arguably the most common rim size globally, as all bolt actions chambered in cartridges derived from that shell, such as .30-06 Springfield, .308 Winchester and cartridges derived from them, share this rim size. The case length was chosen to be compatible with the Barnes 300-grain X Spitzer bullet. The final case design has base and rim dimensions identical to the .425 Westley Richards, although making .458 SOCOM cases from it is impractical due to the high cost of .425 brass.[2] In 2009, Barnes developed a new bullet specifically for use in the .458 SOCOM, the 300 grain Tipped Triple Shock X, also known as the TTSX or TAC-X.
As noted above, the cartridge was designed to be 100% compatible with the M4 platform. This included the buffer, buffer spring, NATO magazines, many aftermarket .223/5.56 magazines, and magazine well. In .223/5.56 caliber, cartridges stack in a staggered (double stack) fashion. However, with the much larger .458 SOCOM, rounds "single stack" without any modification to the standard GI magazine feed lips or follower. A standard 20-round 5.56mm NATO magazine can hold seven .458 SOCOM rounds and a standard 30-round 5.56mm NATO magazine can hold ten .458 SOCOM rounds.[citation needed]
Ralph M. Lermayer, Rifle Review:.458 SOCOM, military.com
The website dedicated to the .458SOCOM, where load data and other info also available.
.458 SOCOM Forums
January 24, 2023
socom, 40mm, moderately, large, round, designed, work, platform, this, achieved, installing, bolt, barrel, grain, round, offers, supersonic, muzzle, velocity, similar, light, with, much, smaller, case, 55gr, nato, 500gr, typerifleplace, originunited, statespro. The 458 SOCOM 11 63 40mm is a moderately large round designed to work in an AR 15 platform This is achieved by installing a 458 bolt and barrel The 300 grain 19 g round offers a supersonic muzzle velocity of 1 900 ft s 580 m s and 2 405 ft lbf 3 261 J 1 similar to a light 45 70 but with a much smaller case 458 SOCOM55gr 5 56 NATO vs 500gr 458 SOCOMTypeRiflePlace of originUnited StatesProduction historyDesignerTeppo Jutsu LLCManufacturerSouthern Ballistic Research SBR Steinel Ammunition IncSpecificationsParent case 50 Action ExpressCase typeRebated rim bottleneckBullet diameter11 63 mm 0 458 in Neck diameter12 32 mm 0 485 in Shoulder diameter13 49 mm 0 531 in Base diameter13 74 mm 0 541 in Rim diameter12 01 mm 0 473 in Rim thickness1 04 mm 0 041 in Case length40 00 mm 1 575 in Overall length57 40 mm 2 260 in Rifling twist1 in 14 most common or 18 Primer typeLarge PistolMaximum pressure35 000 psi 241 MPa Ballistic performanceBullet mass type Velocity Energy250 gr 16 g SP 655 m s 2 150 ft s 3 478 J 2 565 ft lbf 300 gr 19 g HP 580 m s 1 900 ft s 3 261 J 2 405 ft lbf 325 gr 21 g FTX 566 m s 1 860 ft s 3 384 J 2 496 ft lbf 405 gr 26 g JFP 489 m s 1 600 ft s 3 148 J 2 322 ft lbf 600 gr 39 g RN 304 8 m s 1 000 ft s 1 811 J 1 336 ft lbf Contents 1 History 2 See also 3 References 4 External linksHistory EditPrompted by the lack of power offered by the 5 56 NATO cartridge used in the M4 carbine and the M16 rifle the 458 SOCOM came about from informal discussion of members of the special operations command specifically Task Force Ranger s experience that multiple shots were required to incapacitate members of the opposing force in Mogadishu during Operation Gothic Serpent Marty ter Weeme of Teppo Jutsu and Tony Rumore of Tromix designed the cartridge in 2000 and Tromix was contracted to build the first 458 SOCOM rifle in February 2001 The project sponsor set forth a number of specific requirements namely that the cartridge had to fit in the M4 carbine and be capable of firing heavy for caliber projectiles at subsonic velocity using suppressors During the development phase various other cartridges were considered and proposed to the project sponsor but rejected as not meeting all the requirements The cartridges considered were 7 62 39mm 9 39mm Grom 45 Professional which has since become the 450 Bushmaster and 50 Action Express At the time the 499 LWR cartridge was still in the development phase and had not been chambered commercially The 45 Professional was ruled out because in an interview with industry press the developer of said cartridge stated that steel proprietary to General Motors was used in the bolts and extractor to withstand the high operating pressures The 50 AE and 499 LWR were ruled out because in 2000 only two bullets were offered in 501 diameter both developed as pistol bullets for the 50 AE and not heavy enough for the subsonic suppressed role Research had indicated that a short belted cartridge called the 458 1 5 Barnes had been adopted for use in suppressed bolt action rifles for use in South East Asia during the Vietnam War It was shown as effective in terms of ballistics firing a 500 grain bullet subsonically but not ideally suited for its role due to the size and weight of the platform Combined with the wide selection of bullets available in 458 diameter this cemented the choice of caliber The cartridge case design was finalized based on discussions with Tony Rumore at Tromix suggesting a lengthened 50 AE case would work well in the magazines as well as be the largest diameter case to be able to feed through the barrel extension The initial prototype brass still bore the 50 AE head stamp and this has caused some confusion as the SOCOM case is longer with a narrower rim The 50 AE rim diameter was reduced from 514 inch to 473 inch for compatibility with other platforms primarily bolt action rifles The 473 inch 12mm diameter rim was designed in 1888 for the German Commission Rifle chambered in 7 92 57mm Mauser cartridge and is arguably the most common rim size globally as all bolt actions chambered in cartridges derived from that shell such as 30 06 Springfield 308 Winchester and cartridges derived from them share this rim size The case length was chosen to be compatible with the Barnes 300 grain X Spitzer bullet The final case design has base and rim dimensions identical to the 425 Westley Richards although making 458 SOCOM cases from it is impractical due to the high cost of 425 brass 2 In 2009 Barnes developed a new bullet specifically for use in the 458 SOCOM the 300 grain Tipped Triple Shock X also known as the TTSX or TAC X As noted above the cartridge was designed to be 100 compatible with the M4 platform This included the buffer buffer spring NATO magazines many aftermarket 223 5 56 magazines and magazine well In 223 5 56 caliber cartridges stack in a staggered double stack fashion However with the much larger 458 SOCOM rounds single stack without any modification to the standard GI magazine feed lips or follower A standard 20 round 5 56mm NATO magazine can hold seven 458 SOCOM rounds and a standard 30 round 5 56mm NATO magazine can hold ten 458 SOCOM rounds citation needed See also EditThumper concept List of AR platform cartridges List of rifle cartridges 11 mm caliber 458 HAM R 458 Winchester Magnum 450 Bushmaster 375 SOCOM 45 Raptor 50 Beowulf 50 Alaskan 45 70 Government 12 7 55mm STs 130References EditThis article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources 458 SOCOM news newspapers books scholar JSTOR August 2010 Learn how and when to remove this template message Teppo Jutsu 458 SOCOM FAQ Archived 2007 10 06 at the Wayback Machine The Teppo Jutsu range of cartridgesExternal links EditRalph M Lermayer Rifle Review 458 SOCOM military comThe website dedicated to the 458SOCOM where load data and other info also available 458 SOCOM Forums Retrieved from https en wikipedia org w index php title 458 SOCOM amp oldid 1117664600, wikipedia, wiki, book, books, library,
