Munitions

.357 Magnum cartridge

Also known as
  • 357 Magnum
  • .357 Mag

The .357 Magnum is a U.S. rimmed centerfire revolver cartridge developed from the .38 Special in the 1930s and lengthened so its higher-pressure loads would not chamber in standard .38 Special revolvers. Winchester still catalogs factory loads for the round, SAAMI and C.I.P. publish pressure and dimensional standards, and current Marlin, Henry, Rossi, and Ruger firearms show the chambering's continued revolver, rifle, and carbine compatibility.

.357 Magnum cartridge, Revolver cartridge, Munitions
Image source: Cartridge .357 Magnum.jpg
Representative Winchester Loads

Winchester catalogs the cartridge across defensive handgun loads, with bullet weight and load line varying by product family.

LoadBulletUse
X357MBB157-grain semi-jacketed hollow pointBig Bore line for personal defense and hunting.
W357ST145-grain JHPSilvertip line for personal defense.
S357MPDB125-grain bonded jacketed hollow pointDefender line for personal defense.

Source labels used here: X357MBB - Winchester Ammunition, W357ST - Winchester Ammunition, and S357MPDB - Winchester Ammunition.

Design Relationship To .38 Special

The .357 Magnum kept the .38 Special bullet diameter family but used a longer case and higher working pressure. Winchester and American Rifleman both describe the longer case as a safety measure to keep magnum ammunition out of standard .38 Special revolvers.

Parent cartridge

Developed from .38 Special high-performance revolver work rather than as a larger-bore cartridge.

Case distinction

SAAMI lists the .357 Magnum case at 1.290 in / 32.77 mm and maximum cartridge length at 1.590 in / 40.39 mm.

Pressure standards

SAAMI lists a 35,000 psi maximum average pressure, while C.I.P. lists Pmax at 3000 bar by transducer method.

Source labels used here: The 38 Special Vs the .357 Mag - Winchester Ammunition, This Old Gun: Smith & Wesson Registered Magnum - American Rifleman, SAAMI Z299.3-2022 - SAAMI, and 357 Magnum - C.I.P.

Profile / Specs

Profile

Origin
United States
Type
Revolver cartridge
Service note
Introduced in 1934; still in production
Designer
Elmer Keith / Phillip B. Sharpe
Designed
1934
Produced
1934-present

Specifications

Cartridge type
Rimmed centerfire handgun cartridge
Case length
32.77 mm / 1.290 in
Overall length
40.39 mm / 1.590 in maximum
Bullet diameter
9.12 mm C.I.P.; .3580 in minus .0030 SAAMI projectile diameter
Rim diameter
11.18 mm / .440 in
C.I.P. maximum pressure
3000 bar Pmax, transducer method
SAAMI maximum average pressure
35,000 psi
Representative load
Winchester Big Bore X357MBB, 157-grain SJHP
Current firearm examples
Marlin Model 1894 lever-action rifles, Henry .357 Magnum/.38 Spl rifles and carbines, Rossi R95 lever-action rifle, and Ruger 77/357 bolt-action rifle
Related Revolver Cartridge

Winchester describes .357 Magnum in direct comparison with 38 Special, including the longer .357 Magnum case and the revolver-chambering boundary between the two cartridges.

Compatible itemItem typeCompatibility evidence
38 Special, Rimmed centerfire revolver cartridge, Munitions38 SpecialPredecessor revolver cartridge

Winchester describes .357 Magnum as a longer-case cartridge developed from 38 Special performance demands, with 38 Special ammunition usable in many .357 Magnum revolvers but .357 Magnum ammunition not usable in 38 Special revolvers.

Sources: The 38 Special Vs the .357 Mag - Winchester Ammunition

Compatible Handguns

Winchester lists .357 Magnum among its handgun ammunition calibers, while current firearm makers also catalog rifle and carbine chamberings for the cartridge.

Compatible itemItem typeCompatibility evidence
Handgun/pistol, Handheld small arm / sidearm, Infantry WeaponsHandgun/pistolHandgun and pistol platform

Winchester lists .357 Magnum among its handgun ammunition calibers, so the general handgun and pistol page links to this cartridge family explicitly.

Sources: Handgun Ammo - Winchester Ammunition

Current Rifle And Carbine Chamberings

Commercial firearm makers continue to catalog .357 Magnum chamberings outside revolvers, especially in lever-action rifles and carbines that also accept .38 Special ammunition where the manufacturer specifies that compatibility.

MakerFirearmDocumented chambering
MarlinModel 1894 Classic and Trapper lever-action riflesMarlin lists .357 Magnum chambering, tubular-magazine capacity for .357 Magnum and .38 Special, and reliable feeding with factory ammunition.
Henry.357 Magnum/.38 Spl rifle and carbine catalogHenry groups Big Boy, Classic, X Model, carbine, revolver, and related firearms under a .357 Magnum/.38 Spl caliber page.
RossiR95 lever-action rifleRossi lists item 950357201 as a .357 MAG lever-action rifle with 10-round capacity and a 20-inch barrel.
Ruger77/357 bolt-action rifleRuger lists Model 7420 as a 357 Mag bolt-action rifle with 5-round capacity and an 18.50-inch barrel.

Source labels used here: Classic Series Model 1894 - Marlin Firearms, Trapper Series Model 1894 - Marlin Firearms, .357 Magnum/.38 Spl Caliber Firearms - Henry Repeating Arms, R95 Lever Action .357 Mag - Rossi USA, and Ruger 77/357 Model 7420 - Ruger.

Timeline

.357 Magnum cartridge Key Events

  1. .357 Magnum development work

    Winchester describes the cartridge as a 1934 design that extended the .38 Special case; American Rifleman credits Phillip B. Sharpe, Elmer Keith, Douglas Wesson, Smith & Wesson, and Winchester in the development context.

  2. Registered Magnum chambering reaches market

    American Rifleman identifies the Smith & Wesson Registered Magnum as the revolver built around the new .357 Magnum chambering, while Rock Island Auction notes the model was sold by Smith & Wesson from 1935 to 1939.

  3. SAAMI drawing issued

    SAAMI's centerfire pistol and revolver standard lists the .357 Magnum drawing as issued on May 29, 1979 and revised on July 6, 2021.

  4. C.I.P. TDCC entry dated

    The C.I.P. tabulation for 357 Magnum is dated June 14, 1984, with a listed U.S. country of origin and a 2014 revision.

Media

.357 Magnum cartridge Videos

.357 Magnum cartridge Images

.357 Magnum cartridge, Revolver cartridge, Munitions - view 1
Source: Cartridge .357 Magnum.jpg
.357 Magnum cartridge, Revolver cartridge, Munitions - view 2
Source: Cartridge .357 Magnum.jpg
Related Weapon Systems
.44 Smith & Wesson Special cartridge, Revolver cartridge, MunitionsMunitions.44 Smith & Wesson Special cartridgeRevolver cartridgeThe .44 Smith & Wesson Special is a U.S. rimmed centerfire revolver cartridge developed from the .44 Russian lineage for Smith & Wesson's New Century / Triple Lock revolver context. C.I.P. lists the cartridge at 29.46 mm case length, 41.02 mm overall length, and 1000 bar Pmax, while SAAMI lists 15,500 psi MAP and recognizes 44 S&W Spl as the abbreviated name. Later .44 Remington Magnum development used the .44 Special case family as its starting point.
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.40 S&W cartridge, Semi-automatic pistol cartridge, MunitionsMunitions.40 S&W cartridgeSemi-automatic pistol cartridge.40 S&W is an American centerfire semi-automatic pistol cartridge introduced by Smith & Wesson and Winchester Ammunition in 1990. It packaged the FBI's reduced-velocity 10mm service-load concept into a shorter cartridge suitable for 9mm-size duty pistols, while SAAMI and C.I.P. standards define the cartridge's pressure and dimensional limits. The strongest documented context is design history, specifications, and firearm compatibility rather than conflict-specific battlefield use.
.338 Lapua Magnum cartridge, 8.6 mm long-range centerfire rifle cartridge, MunitionsMunitions.338 Lapua Magnum cartridge8.6 mm long-range centerfire rifle cartridge.338 Lapua Magnum is a Finnish 8.6x70 mm centerfire rifle cartridge developed from .338/416 work into a long-range military, law-enforcement, and precision-rifle round. C.I.P. lists Finland as the country of origin, while Lapua and Nammo sources show current tactical, target, armor-piercing, hunting, and special-purpose load families. The linked rifle relationships stay limited to cataloged weapons whose sources document .338 Lapua chambering.
.300 Norma Magnum, Long-range centerfire rifle cartridge, MunitionsMunitions.300 Norma MagnumLong-range centerfire rifle cartridge.300 Norma Magnum is a Swedish-origin long-range centerfire rifle cartridge in the Norma Magnum family. Norma presents the caliber as a modern precision cartridge tied to its earlier .308 Norma Mag lineage, while C.I.P. lists Sweden as country of origin and SAAMI later accepted the 300 Norma Magnum for standardization. The record links documented chambered rifles such as the Barrett MRAD / MK22 and PGW Timberwolf Gen 3 without turning those relationships into conflict-use claims.
45 Automatic (45 Auto), Rimless centerfire pistol cartridge, MunitionsMunitions45 Automatic (45 Auto)Rimless centerfire pistol cartridge45 Automatic (45 Auto) is SAAMI's recognized name for the .45 ACP cartridge developed around John Browning and Colt's early self-loading pistol work and adopted by the U.S. Army with the Model 1911 pistol. This relationship-only page covers the cartridge as a standardized handgun and submachine-gun round, with SAAMI and C.I.P. dimensions, U.S. military ball-cartridge context, current commercial loads, and a sourced compatibility link to the Glock 21 family.

Sources

The 38 Special Vs the .357 Mag - Winchester AmmunitionPublisher: Winchester Ammunition | Note: Supports the .357 Magnum's 1934 origin context, the longer case redesign, and the relationship to .38 Special revolver chambering. | Accessed: 2026-07-03Handgun Ammo - Winchester AmmunitionPublisher: Winchester Ammunition | Note: Supports Winchester's handgun ammunition lineup and the explicit inclusion of .357 Magnum among its popular handgun calibers. | Accessed: 2026-06-27Classic Series Model 1894 - Marlin FirearmsPublisher: Marlin Firearms | Note: Supports current .357 Magnum rifle compatibility through Marlin's Model 1894 Classic chambering, capacity, and factory-ammunition feeding description. | Accessed: 2026-07-03Trapper Series Model 1894 - Marlin FirearmsPublisher: Marlin Firearms | Note: Supports current .357 Magnum and .38 Special ammunition compatibility in a Marlin Model 1894 Trapper lever-action rifle. | Accessed: 2026-07-03.357 Magnum/.38 Spl Caliber Firearms - Henry Repeating ArmsPublisher: Henry Repeating Arms | Note: Supports current .357 Magnum/.38 Special rifle, carbine, revolver, and related firearm chamberings in Henry's product catalog. | Accessed: 2026-07-03R95 Lever Action .357 Mag - Rossi USAPublisher: Rossi USA | Note: Supports current .357 Magnum compatibility for Rossi's R95 lever-action rifle, including caliber, action type, capacity, and barrel-length listing. | Accessed: 2026-07-03Ruger 77/357 Model 7420 - RugerPublisher: Sturm, Ruger & Co. | Note: Supports current .357 Magnum compatibility for Ruger's 77/357 bolt-action rifle, including caliber, capacity, barrel length, and rotary-magazine listing. | Accessed: 2026-07-03X357MBB - Winchester AmmunitionPublisher: Winchester Ammunition | Note: Supports the representative .357 Magnum Big Bore load data and the 157-grain semi-jacketed hollow point load line. | Accessed: 2026-06-27W357ST - Winchester AmmunitionPublisher: Winchester Ammunition | Note: Supports the representative .357 Magnum Silvertip load data and the 145-grain personal-defense load line. | Accessed: 2026-06-27S357MPDB - Winchester AmmunitionPublisher: Winchester Ammunition | Note: Supports the representative .357 Magnum Defender load data and the 125-grain personal-defense load line. | Accessed: 2026-06-27This Old Gun: Smith & Wesson Registered Magnum - American RiflemanPublisher: American Rifleman | Note: Supports the .357 Magnum development context, the .38 Special case relationship, the Registered Magnum chambering, and the roles of Sharpe, Keith, Douglas Wesson, Smith & Wesson, and Winchester. | Accessed: 2026-07-03Registered Magnum: The Original .357 Revolver - Rock Island AuctionPublisher: Rock Island Auction Company | Note: Supports production context for the Smith & Wesson Registered Magnum, including 1935-1939 registered-production context, later non-registered production, and the reported 5,224 registered revolvers sold by Smith & Wesson. | Accessed: 2026-07-03SAAMI Z299.3-2022 - SAAMIPublisher: Sporting Arms and Ammunition Manufacturers' Institute | Note: Supports SAAMI .357 Magnum naming, 35,000 psi maximum average pressure, cartridge dimensions, and the drawing issue/revision dates. | Accessed: 2026-07-03357 Magnum - C.I.P.Publisher: C.I.P. | Note: Supports the U.S. origin, standard dimensions, and pressure data for the .357 Magnum cartridge. | Accessed: 2026-07-03Cartridge .357 Magnum.jpgPublisher: Wikimedia Commons | Note: Supports image provenance for a high-resolution own-work .357 Magnum cartridge photograph licensed CC BY-SA 4.0 on Wikimedia Commons. | Accessed: 2026-06-27.357 Magnum.pngPublisher: Wikimedia Commons | Note: Supports image provenance for an own-work .357 Magnum maximum C.I.P. cartridge-dimensions diagram released as CC0 on Wikimedia Commons. | Accessed: 2026-06-27.357 Magnum.jpgPublisher: Wikimedia Commons | Note: Supports image provenance for a self-published own-work .357 Magnum cartridge photograph licensed CC BY-SA 4.0 on Wikimedia Commons; retained as a secondary gallery image. | Accessed: 2026-06-27