.357 SIG

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.357 SIG
357 SIG - FMJ - SB - 1.jpg
.357 SIG Jacketed Flat Point cartridge
Type Pistol
Place of origin   Switzerland
 United States
Production history
Designer SIGARMS / Federal Cartridge Co.
Designed 1994
Produced 1994–present
Specifications
Parent case 10mm Auto
Case type Rimless, bottleneck
Bullet diameter 9.02 mm (0.355 in)
Neck diameter 9.68 mm (0.381 in)
Shoulder diameter 10.77 mm (0.424 in)
Base diameter 10.77 mm (0.424 in)
Rim diameter 10.77 mm (0.424 in)
Rim thickness 1.40 mm (0.055 in)
Case length 21.97 mm (0.865 in)
Overall length 28.96 mm (1.140 in)
Case capacity 1.27 cm3 (19.6 gr H2O)
Rifling twist 406 mm (1 in 16 in)
Primer type Small pistol
Maximum pressure (C.I.P.) 305.0 MPa (44,240 psi)
Maximum pressure (SAAMI) 275.8 MPa (40,000 psi)
Ballistic performance
Bullet weight/type Velocity Energy
115 gr (7 g) Doubletap Bonded defense JHP 1,550 ft/s (470 m/s) 614 ft·lbf (832 J)
125 gr (8 g) Doubletap FMJ-FP Match and Bonded defense JHP 1,450 ft/s (440 m/s) 584 ft·lbf (792 J)
147 gr (10 g) DoubletapBonded defense JHP 1,250 ft/s (380 m/s) 510 ft·lbf (690 J)
147 gr (10 g) DoubletapFMJ-FP 1,255 ft/s (383 m/s) 514 ft·lbf (697 J)
Test barrel length: 4 in (102 mm) rifled barrel.
Source(s): DoubleTap Ammunition, C.I.P.[1]

The .357 SIG pistol cartridge (designated as the 357 Sig by the SAAMI [2] and 357 SIG by the C.I.P.[1]) is the product of Swiss-German firearms manufacturer SIG Sauer, in cooperation with the American ammunition manufacturer Federal Cartridge. While it is based on a .40 S&W case necked down to accept 0.355-inch (9.0 mm) bullets, the .357 SIG brass is slightly longer by 0.009 in (0.23 mm) to 0.020 in (0.51 mm) total. The cartridge is used by a number of law enforcement agencies and has a good reputation for both accuracy and stopping power.[3]

History

Developed in 1994, the new cartridge was named "357" to highlight its purpose: to duplicate the performance of 125-grain (8.1 g) .357 Magnum loads fired from 4-inch (100 mm) barreled revolvers, in a cartridge designed to be used in a semi-automatic pistol with greater ammunition capacity than a revolver. Performance is similar to the 9×23mm Winchester.

Other than specialized competition cartridges like the 9×25mm Dillon (1988), which necked a 10mm Auto case down to a 9mm bullet, the .357 SIG (1994) was the first modern bottleneck commercial handgun cartridge since the early 1960s, when Winchester introduced a .257 caliber round based on the .357 Magnum, the now obsolete .256 Winchester Magnum (1960). Then Remington introduced the unsuccessful .22 Remington Jet (1961), which necked a .357 Magnum case down to a .22 caliber bullet, and the .221 Remington Fireball (1963), a shortened version of their .222 Remington. Soon after the .357 SIG, other bottleneck commercial handgun cartridges appeared: the .400 Corbon (1996), necking the .45 ACP down to .40 caliber; the .440 Corbon (1998), necking down the .50 AE to .44 caliber; the .32 NAA (2002), necking the .380 ACP down to .32 caliber; and the .25 NAA (2004), necking the .32 ACP down to .25 caliber.

Cartridge dimensions

The .357 SIG has 1.27 ml (19.5 grains H2O) cartridge case capacity.

.357 SIG maximum C.I.P. cartridge dimensions.[1] All sizes in millimeters.

Americans would define the shoulder angle at alpha/2=18 degrees. The common rifling twist rate for this cartridge is 406 mm (1 in 16 in), 6 grooves, Ø lands=8.71 mm, Ø grooves=9.02 mm, land width=2.69 mm and the primer type is small pistol.

Several sources have published contradicting information regarding .357 SIG headspacing.[4] This is due to originally designed as .357 (9.02mm) round but has been rapidly adapted to .355 (9mm) bullet.

According to the official C.I.P. (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portatives) 2007 rulings the .357 SIG headspaces on the shoulder (P2-H1). Some US sources concur this C.I.P. ruling.[5] US reloading supplier Lyman once published the .357 SIG headspaces on the case mouth (H2).

According to the C.I.P. rulings the .357 SIG case can handle up to 305 MPa (44,236 psi) piezo pressure. In C.I.P. regulated countries every pistol cartridge combo has to be proofed at 130% of this maximum C.I.P. pressure to certify for sale to consumers.
The SAAMI pressure limit for the .357 SIG is set at 275.80 MPa (40,000 psi), piezo pressure.[6]

Conversions

Left to right: .357 SIG, 10mm Auto, .40 S&W

Most .40 S&W pistols can be converted to .357 SIG by replacing the barrel, but sometimes the recoil spring must be changed as well. Pistols with especially strong recoil springs can accept either cartridge with a barrel change. Magazines will freely interchange between the two cartridges in most pistols. .357 SIG barrel kits have allowed this cartridge to gain in popularity among handgun owners. However, the .357 SIG is loaded to higher pressures than the .40 S&W (the C.I.P. and the SAAMI pressure limits for .40 S&W are 225 MPa and 35,000 psi), and may not be suitable for use in all .40 S&W-chambered pistols due to the increase in bolt thrust.

Performance

The table below shows common performance parameters for several .357 SIG loads. Bullet weights ranging from 115 to 150 grains (7.5 to 9.7 g) have been offered. Loads are available with energies from 488 foot-pounds force (662 J) to over 568 foot-pounds force (770 J), and penetration depths from 9 inches (230 mm) to over 16.5 inches (420 mm) are available for various applications and risk assessments.

Manufacturer Load Mass Velocity Energy Expansion[7] Penetration [7] PC[7] TSC[7]
Triton Quik-Shok 115 gr (7.5 g) 1,425 ft/s (434.3 m/s) 518 ft·lbf (702.3 J) frag 9.0 in (228.6 mm) 4.1 cu in (67.2 cm3) 43.2 cu in (707.9 cm3) (est)
Winchester Ranger T 125 gr (8.1 g) 1,385 ft/s (422.1 m/s) 532 ft·lbf (721.3 J) 0.75 in (19.1 mm) 11.5 in (292.1 mm) 5.1 cu in (83.6 cm3) 45.0 cu in (737.4 cm3) (est)
Federal Premium JHP 125 gr (8.1 g) 1,430 ft/s (435.9 m/s) 568 ft·lbf (770.1 J) 0.62 in (15.7 mm) 12.7 in (322.6 mm) 3.8 cu in (62.3 cm3) 49.5 cu in (811.2 cm3) (est)
Speer Gold Dot JHP 125 gr (8.1 g) 1,385 ft/s (422.1 m/s) 532 ft·lbf (721.3 J) 0.68 in (17.3 mm) 16.5 in (419.1 mm) 6.0 cu in (98.3 cm3) 45.0 cu in (737.4 cm3) (est)
Remington JHP 125 gr (8.1 g) 1,350 ft/s (411.5 m/s) 506 ft·lbf (686.0 J) 0.57 in (14.5 mm) 14.3 in (363.2 mm) 3.6 cu in (59.0 cm3) 41.7 cu in (683.3 cm3) (est)
Federal Premium JHP 150 gr (9.7 g) 1,210 ft/s (368.8 m/s) 488 ft·lbf (661.6 J) 0.60 in (15.2 mm) 15.0 in (381.0 mm) 4.2 cu in (68.8 cm3) 39.4 cu in (645.7 cm3) (est)
Underwood Gold Dot JHP 125 gr (8.1 g) 1,505 ft/s (458.7 m/s) 605 ft·lbf (820.3 J) 0.75 in (19.1 mm) 16.5 in (419.1 mm) 6.0 cu in (98.3 cm3) 45.0 cu in (737.4 cm3) (est)


Key:
Expansion – expanded bullet diameter (ballistic gelatin).
Penetration – penetration depth (ballistic gelatin).
PC – permanent cavity volume (ballistic gelatin, FBI method).
TSC – temporary stretch cavity volume (ballistic gelatin).

Because of its relatively high velocity[8] for a handgun round, the .357 SIG has an unusually flat trajectory, extending the effective range. However, it does not quite reach the performance of the .357 Magnum with bullets heavier than 125 grains (8.1 g). Offsetting this general slight disadvantage in performance is that semi-automatic pistols tend to carry considerably more ammunition than revolvers.

The Virginia State Police has reported that attacking dogs have been stopped dead in their tracks by a single shot, whereas the former 147 grain 9 mm duty rounds would require multiple shots to incapacitate the animals.[9] Proponents of the hydrostatic shock theory contend that the energy available in the .357 SIG is sufficient for imparting hydrostatic shock with well-designed bullets.[10][11][12] Users have commented, "We're really impressed with the stopping power of the .357 SIG round."[3]

The bottleneck shape of the .357 SIG cartridge makes feeding problems almost non-existent.[13] This is because the bullet is channeled through the larger chamber before being seated entirely as the slide goes into full battery. Flat point bullets are seldom used with other autoloader platforms because of feeding problems; however, such bullets are commonly seen in the .357 SIG chambering and are quite reliable, as are hollow-point bullets.

The "Accurate Powder" reloading manual claims that it is "without a doubt the most ballistically consistent handgun cartridge we have ever worked with."[6]

Characteristics

From left to right: 9mm, 7.62×25mm Tokarev, .357 SIG, 10mm Auto, .40 S&W, .45 GAP, .50 AE.

The goal of the .357 SIG project was to offer a level of performance equal to the highly effective 125-grain (8.1 g) .357 Magnum load.[14][15] The .357 SIG accomplishes this with a 125-grain (8.1 g) bullet at a muzzle velocity of 1,450 feet per second (440 m/s) out of a 4 in (102 mm) barrel, which is generally identical to the velocity achieved by standard factory 125-grain (8.1 g) .357 Magnum loads out of a 4 in (102 mm) revolver barrel.[citation needed]

With a simplistic approach to physics, recoil being directly proportional to "muzzle velocity × bullet mass" (due to conservation of momentum), the recoil of the .357 SIG is equal to or slightly less than that of the .40 S&W, and less than that of the full-power 10mm Auto loads or the original .357 Magnum,[16] Handgun Recoil table as well as Street Stoppers[17] This simple approach to recoil is incomplete since the properties of the bullet alone do not determine the felt recoil, but also the rocket-like blast of propellant gases coming out of the barrel after the bullet leaves the muzzle.[18] A more accurate view on recoil is that it is proportional to the mass of all ejecta × velocity of ejecta.[19] Even so, recoil calculated in this manner is only the starting point in a comparison with the .357 Magnum cartridge, since the latter is used in a revolver, in which the recoil energy is due to the Bullet and propellant less ejecta escaping between the cylinder and breech, while the .357 SIG cartridge is used in a semi-automatic pistol with recoil operation; here, a significant portion of the recoil energy is diverted to cycle the action, effectively prolonging the recoil-phase pulse. Of course, other considerations affect the user's perceived recoil, such as the weight of the weapon, front to back balance, moving mass, height difference between the shooter's grip parallel to the barrel, and grip.

In comparing the energy levels of premium self-defense ammunition, the muzzle energy of 584 ft·lbf (792 J) of the 125 grains (8.1 g) 1,450 feet per second (440 m/s) .357 SIG load is greater than either the 475 ft·lbf (644 J) generated by a 155 grains (10.0 g) 1,175 feet per second (358 m/s) Speer GoldDot .40 S&W load or the 400 ft·lbf (540 J) generated by a 180 grains (12 g) 985 feet per second (300 m/s) Speer GoldDot .40 S&W load.[20]

Like the 10mm Auto, the .357 SIG can be down-loaded to reduce recoil to the point where recoil is similar to that of a 9×19mm Parabellum. However, since the .357 SIG uses bullets that are generally the same as those used in the 9 mm Para,[21] downloading it to this point would defeat the purpose of fielding the SIG cartridge, as the .357 SIG casing was designed to handle up to 160 gr bullets whereas the less-powerful 9mm maxes out at 147 gr bullet weight in subsonic loads.

Because the .357 SIG fires at relatively high pressures, muzzle flash and report can be significant with standard loads, even with longer barrels. Utilizing loads with specialized powders and various bullet weights might reduce flash.

Implementation

Oblique view of a .357 SIG FMJ cartridge.

In 1994, Sig released the P229 pistol, the first production handgun introduced that was chambered in .357 SIG and specifically designed to handle the higher pressures of that round.[22]

From 1991 to 1998, the Texas Department of Public Safety (DPS) issued either the SIG Sauer P220 in .45 ACP or the SIG Sauer P226 in 9mm Parabellum at the Trooper's discretion. In 1998, the Texas DPS transitioned to the all-steel, full-sized (34.0 oz) SIG Sauer P226 chambered in the .357 SIG cartridge as the solitary choice of pistol for commissioned officers. In doing so, the Texas DPS became the first government agency to deploy a firearm utilizing the then relatively new .357 SIG chambering.

However, in 2013 the Texas DPS decided to replace their .357 SIG handguns with 9mm handguns.[23] The ability to carry more rounds per magazine (9mm vs. .357 SIG) in a lighter gun were among the stated reasons for the change.[24] That transition was suspended after recruits in the A-2014 class, the first to train with the new S&W M&P 9mm polymer handguns, experienced numerous malfunctions with those weapons.[25]

The newer SIG Sauer P229 in .357 SIG has been adopted for use by agents and officers of the following national and state law enforcement organizations (LEO):

The Tennessee Highway Patrol currently issues the Glock 31 pistol chambered in .357 SIG. The Mississippi Highway Patrol issues the Glock 31 Gen4 in .357 SIG.[29][30] The Bedford Heights Police Department in Ohio currently issues the Glock 31/32/33. The Elloree Police Department in South Carolina also issues the Glock 31 in .357 SIG, and the Madison Police Department in Madison, WV issues the Glock 32 in .357 SIG. The Gouverneur Police Department in New York issues the Glock 32. The Lexington Police Department in North Carolina issues the SIG Sauer P229 DAK in .357 SIG. The Oklahoma Highway Patrol and Rhode Island State Police issue the SIG Sauer P226 in .357 SIG. The Paramus Police Department in New Jersey also issues the SIG P229 in .357 SIG. The West Grove Borough Police Department, West Grove PA, also carry the SIG Sauer P229 in the .357 SIG caliber. Both the New Mexico State Police[31] and the North Carolina State Highway Patrol use SIG Sauer P229s chambered in .357 SIG. The Herculaneum (Missouri) Police Department uses the P229 and P226 in .357 SIG. The Coral Springs Police Department in Florida uses the Sig P226 and P229 Enhanced Elite pistols chambered in .357 SIG.[32] The Orlando Police Department uses the SIG Sauer P229 in .357 SIG.[33] In July 2014 it was announced that the North Carolina State Highway Patrol will equip its 1,600 officers with the SIG Sauer P226 in .357 SIG.[34]

See also

References

  1. ↑ 1.0 1.1 1.2 C.I.P. TDCC datasheet 357 SIG
  2. ↑ SAAMI 357 Sig cartridge and chamber drawings
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 The Gun Digest Book of Sig-Sauer: a complete look at Sig-Sauer pistols. Massad Ayoob. 2004. pp. 51–53.
  4. ↑ 357 SIG handload reliability...controlling headspace By Joseph D'Alessandro Editor RealGuns.Com
  5. ↑ The return of the giant .357 Headspace Part I By Joseph D'Alessandro Editor RealGuns.Com
  6. ↑ 6.0 6.1 ".357 SIG" data from Accurate Powder. Accessed 2009-06-09. Archived 2009-06-11.
  7. ↑ 7.0 7.1 7.2 7.3 Marshall and Sanow, Stopping Power, Paladin 2001, p. 75.
  8. ↑ Ballistics By The Inch .357Sig results
  9. ↑ Ayoob, Massad. (2002). The Gun Digest Book of Combat Handgunnery, 5th edition: Krause Publications. ISBN 0-87349-485-7
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ Sturtevant B, Shock Wave Effects in Biomechanics, Sadhana, 23: 579–596, 1998.
  12. ↑ Courtney A, Courtney M: Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities. Brain Injury 21(7): 657–662, 2007.
  13. ↑ Gun Digest Buyer's Guide to Concealed-Carry Handguns By Jerry Ahern. 2010. p. 35.
  14. ↑ recorded results in Street Stoppers pg 173 .357 Magnum and Handgun Stopping Power by Marshall & Sanow
  15. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  16. ↑ Lyman Reloading Handbook, 43rd Edition
  17. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  18. ↑ Recoil
  19. ↑ Auto-loader vs Revolver recoil... - THR
  20. ↑ Midway USA page
  21. ↑ Lyman Reloading Handbook, 48th edition, 2002, Lyman Products Corp.
  22. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  23. ↑ Texas Highway Patrol Dropping SIG Pistols in .357 SIG for S&W Pistols in 9mm
  24. ↑ Texas DPS Ditches S&W M&P Handguns Over Reliability Issues
  25. ↑ DPS Suspends Use of New Handgun Over "Concerns" - Myhighplains.com - Powered by KAMR LOCAL 4
  26. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  27. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  28. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  29. ↑ New Glock 31, .357 Testing & Evaluation
  30. ↑ Mississippi Highway Patrol logo on Glock 31 Generation 4
  31. ↑ Smith & Wesson advertisement in Sept. 2010 issue of Tactical Weapons magazine.
  32. ↑ S. Mitchell Coral Springs Police Training Unit Oct 2013
  33. ↑ Police Weapons in the USA: Florida
  34. ↑ North Carolina State Highway Patrol Buy SIG SAUER P226 in .357 SIG

External links

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