.357 SIG

Template:Short description Template:Infobox firearm cartridge

The .357 SIG (designated as the 357 Sig by the SAAMI<ref name="SAAMI-drawing">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and 357 SIG by the C.I.P.<ref name="C.I.P.-TDCC sheet">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> or 9×22 mm in official metric notation) is a bottlenecked rimless centerfire handgun cartridge developed by the Swiss-German firearms manufacturer SIG Sauer, in cooperation with ammunition manufacturer Federal Premium. The cartridge is used by a number of law enforcement agencies.<ref name=ayoob2004>The Gun Digest Book of Sig-Sauer: a complete look at Sig-Sauer pistols. Massad Ayoob. 2004. pp. 51–53.</ref>

HistoryEdit

The .357 SIG is based on a necked-down .40 Smith & Wesson case, forgoing the large pistol primer utilized by the 10mm Auto in favor of the small pistol primer used in many common self-defense rounds, such as .40 S&W, .38 Special, 9 mm and other similarly-sized cartridges. Excluding specialized wildcat cartridges used in competition shooting — e.g., the 9×25mm Dillon, which necked a 10mm Auto case down to a 9 mm bullet — the .357 SIG was the first modern bottlenecked handgun cartridge to become commercially available since the 1961 introduction of Winchester's now-obsolete .256 Winchester Magnum, a .257 caliber round based on the .357 Magnum. Later the same year Remington and Smith & Wesson began jointly developing a similar round and, before the year's end, introduced the .22 Remington Jet, a .357 Magnum case necked down to accommodate a .22 caliber bullet.

Despite its favorable ballistics and performance, the .357 SIG has not achieved the widespread adoption seen with similar cartridges. One factor preventing the round from achieving greater popularity could be the cost of the ammunition, which frequently reaches double the expense of 9 mm, .40 S&W or .45 ACP ammunition. Because of this, as well as availability issues, some law enforcement agencies that previously adopted the cartridge have reportedly began to move away from the .357 SIG in favor of more common rounds with comparable performance.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Cartridge dimensionsEdit

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

File:357 SIG.svg

.357 SIG maximum C.I.P. cartridge dimensions.<ref name="C.I.P.-TDCC sheet"/> All sizes in millimeters.

Several sources have published contradicting information regarding .357 SIG headspacing.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> This is due to the cartridge having been originally designed as a .357 (9.02 mm) round, but then rapidly adapted to the .355 (9 mm) bullet. According to the official C.I.P. (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portatives) 2008 revised documents, the .357 SIG headspaces on the case mouth (H2).<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Some US sources are in conflict with this standard.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> However, the cartridge and chamber drawing in the ANSI/SAAMI American National Standards also clearly shows the cartridge headspacing on the case mouth.<ref>Template:Cite book</ref> Likewise, US reloading supplier Lyman has published that the .357 SIG headspaces on the case mouth.

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.<ref name="accurate">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

ConversionsEdit

File:357SIG ammo.jpg

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

While it is based on a 10 mm case necked down to accept Template:Convert bullets, the .357 SIG cartridge case is slightly longer than the .40 S&W by Template:Convert to Template:Convert total. Most .40 S&W pistols can be converted to .357 SIG by replacing the barrel, but sometimes the recoil spring must also be changed. 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.

PerformanceEdit

The table below shows common performance parameters for several .357 SIG loads. Bullet weights ranging from Template:Convert have been offered. Loads are available with energies from Template:Convert to Template:Convert, and penetration depths from Template:Convert to over Template:Convert are available for various applications and risk assessments. Underwood now also offers a standard pressure 65 gr .357 SIG Xtreme Defender (XD) round with a muzzle velocity of 2,100 fps, muzzle energy of 636 ft. lbs. and a penetration depth of 17.5 inches.

Manufacturer	Load	Mass	Velocity	Energy	Expansion<ref name="MS2001">Marshall and Sanow, Stopping Power, Paladin 2001, p. 75.</ref>	Penetration<ref name="MS2001"/>	PC<ref name="MS2001"/>	TSC<ref name="MS2001"/>
Triton	Quik-Shok	Template:Convert	Template:Convert	Template:Convert	frag	Template:Convert	Template:Convert	Template:Convert (est)
Winchester	Ranger T	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert (est)
Federal	Premium JHP	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert (est)
Speer	Gold Dot JHP	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert (est)
Remington	JHP	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert (est)
Federal	Premium JHP	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert (est)
Underwood	Gold Dot JHP	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert	Template:Convert (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<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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 Template:Convert. 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.<ref>Ayoob, Massad. (2002). The Gun Digest Book of Combat Handgunnery, 5th edition: Krause Publications. Template:ISBN</ref> 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.<ref name="arxiv.org">Template:Cite arXiv</ref><ref name="Sturtevant B 1998">Sturtevant B, Shock Wave Effects in Biomechanics, Sadhana, 23: 579–596, 1998.</ref><ref>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.</ref> Users have commented, "We're really impressed with the stopping power of the .357 SIG round."<ref name="ayoob2004"/>

The bottleneck shape of the .357 SIG cartridge makes feeding problems almost non-existent.<ref>Gun Digest Buyer's Guide to Concealed-Carry Handguns By Jerry Ahern. 2010. p. 35.</ref>

The Accurate Powder reloading manual claims that it is "without a doubt the most ballistically consistent handgun cartridge we have ever worked with".<ref name="accurate" />

CharacteristicsEdit

File:9mm 7,62mm 357sig 10mm 45SW 45GAP 50AE 002.jpg

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 Template:Convert .357 Magnum load.<ref>recorded results in Street Stoppers pg 173 .357 Magnum and Handgun Stopping Power by Marshall & Sanow</ref><ref>Template:Cite arXiv</ref> Measurements of standard factory .357 SIG cartridges loaded with Template:Convert bullets showed approximate muzzle velocities of Template:Convert out of a Template:Convert barrel, which is essentially identical to the .357 Magnum with the same bullet weight and barrel length.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> These measurements were performed with a Thompson Center Encore 1842 break-action, single-shot pistol-rifle, preventing differing barrel length definitions between semi-automatic pistols and revolvers giving revolvers a potential muzzle velocity advantage.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

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.<ref>Template:Cite book</ref> This simple approach to recoil is, however, incomplete, since the properties of the bullet alone do not determine the felt recoil; the rocket-like blast of propellant gases exiting the barrel after the bullet leaves the muzzle also plays a role.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> A more accurate view on recoil is that it is proportional to the mass of all ejecta × velocity of ejecta.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

In comparing the energy levels of premium self-defense ammunition, the muzzle energy of Template:Convert of the Template:Convert Template:Convert .357 SIG load is greater than either the Template:Convert generated by a Template:Convert Template:Convert Speer GoldDot .40 S&W load or the Template:Convert generated by a Template:Convert Template:Convert Speer GoldDot .40 S&W load.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

ImplementationEdit

File:357 SIG - FMJ - SB - 3.jpg

Oblique view of a .357 SIG FMJ cartridge.

In 1994 Sig released the P229 pistol, the first production handgun chambered in .357 SIG, specifically designed to handle the higher pressures of that round.<ref name="shootingillustrated357sig">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

However, in 2013 the Texas DPS decided to replace their .357 SIG handguns with 9 mm handguns.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The ability to carry more rounds per magazine (9 mm vs. .357 SIG) in a lighter gun were among the stated reasons for the change.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> That transition was suspended after recruits in the A-2014 class, the first to train with the new S&W M&P 9 mm polymer handguns, experienced numerous malfunctions with those weapons.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

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):