How do .38 Special and .357 Magnum differ?
The .357 Magnum is a lengthened .38 Special loaded to roughly twice the pressure. Both fire a bullet of the same 0.357-inch diameter, but the Magnum case is 0.135 inches longer and its SAAMI maximum average pressure is 35,000 psi against 17,500 psi for standard .38 Special. A revolver chambered in .357 Magnum also accepts .38 Special; the reverse is not true, and the longer case exists to prevent it.
| .38 Special | .357 Magnum | |
|---|---|---|
| Introduced | 1898 (Smith & Wesson) | 1935 (Smith & Wesson; Keith, Sharpe, Wesson) |
| Bullet diameter | 0.357" | 0.357" |
| Case length | 1.155" | 1.290" |
| Maximum overall length | 1.550" | 1.590" |
| SAAMI max pressure | 17,500 psi (+P: 20,000 psi) | 35,000 psi |
| CIP max pressure | — | 44,000 psi (3,000 bar) |
| Typical bullet weights | 110–158gr | 125–180gr |
| Common platforms | Revolvers, a few derringers | Revolvers, lever-action and single-shot rifles |
The side-by-side page at .38 Special vs .357 Magnum shows current observed pricing for both cartridges next to these specifications.
Why is the .357 Magnum case longer?
When Smith & Wesson introduced the .357 Magnum in 1935, the cartridge was a .38 Special case stretched by roughly an eighth of an inch. The extra length is mostly a safety feature rather than a powder-capacity requirement: a .357 Magnum round is too long to fit fully into a .38 Special cylinder, so a high-pressure Magnum load cannot be chambered in an older revolver built only for .38 Special pressures.
The interchange runs one way:
- .38 Special in a .357 Magnum revolver: dimensionally compatible, and routinely done. The shorter case leaves a small gap in the front of the chamber, and heavy use of short cases can leave a carbon or lead ring that makes full-length Magnum cases harder to seat until the chambers are cleaned.
- .357 Magnum in a .38 Special revolver: does not fit by design, and should not be forced.
- .38 Special +P: a higher-pressure .38 Special (SAAMI 20,000 psi). Whether a given .38 Special revolver is rated for +P is stated by its manufacturer; a .357 Magnum revolver handles +P because its rating is far higher.
What do published loads show for velocity and energy?
The figures below are manufacturer-published muzzle velocities. Energy is computed as bullet weight (gr) × velocity² ÷ 450,240, which reproduces each maker's published energy within about one ft-lb.
| Load | Bullet | Velocity | Muzzle energy |
|---|---|---|---|
| Federal American Eagle .38 Special (AE38K) | 130gr FMJ | 890 fps | 229 ft-lbs |
| Winchester Super-X .38 Special (X38S1P) | 158gr LRN | 755 fps | 200 ft-lbs |
| Federal American Eagle .357 Magnum (AE357A) | 158gr JSP | 1,240 fps | 540 ft-lbs |
| Federal .357 Magnum (357B) | 125gr JHP | 1,450 fps | 584 ft-lbs |
At an identical 158-grain bullet weight, the Federal .357 Magnum load is published at 485 fps faster than the Winchester .38 Special load, and its computed energy is 2.7 times higher (540 ÷ 200). Velocities are from manufacturer test barrels; a 2-inch snub-nose revolver produces less velocity than those barrels, and the reduction is typically proportionally larger for the Magnum because more of its powder is still burning when the bullet exits.
How does recoil compare?
Felt recoil depends on the gun's weight, grip, and the powder charge, none of which a box of ammunition states. The part that can be computed from published numbers is bullet momentum — bullet weight (gr) × velocity (fps) ÷ 225,218, in pound-seconds. The gun receives an equal and opposite push from the bullet, plus an additional push from the expanding powder gas.
| Load | Bullet momentum |
|---|---|
| .38 Special 158gr at 755 fps | 0.530 lb·s |
| .38 Special 130gr at 890 fps | 0.514 lb·s |
| .357 Magnum 158gr at 1,240 fps | 0.870 lb·s |
| .357 Magnum 125gr at 1,450 fps | 0.805 lb·s |
On bullet momentum alone, the 158-grain Magnum load produces 1.64 times the rearward impulse of the 158-grain .38 Special load (0.870 ÷ 0.530). The real-world gap is larger than that ratio because the Magnum burns a heavier powder charge, and the gas leaving the muzzle adds to recoil — the method above deliberately leaves out what the published data cannot supply.
Gun weight then divides the impulse. The same 0.870 lb·s acting on a lightweight snub-nose produces a much faster recoil velocity than on a heavy-framed revolver with a 4- or 6-inch barrel. This is why the same .357 Magnum load is described very differently by owners of light and heavy revolvers.
Which firearms are chambered for each?
.38 Special only: many small-frame carry revolvers, such as Smith & Wesson J-frame models built on lightweight alloy frames, along with older police-pattern revolvers. Many are rated for +P; some older or lighter models are not, and the manufacturer's marking or manual is the authority.
.357 Magnum (also fires .38 Special): small-frame revolvers (for example, the Ruger SP101 and Ruger LCR in its .357 version), medium-frame duty revolvers (Smith & Wesson Model 686, Ruger GP100, Colt Python), single-action revolvers, and pistol-caliber lever-action rifles such as the Marlin 1894C, Henry Big Boy, and Rossi R92 in .357 Magnum. In a rifle-length barrel the Magnum gains velocity over its revolver figures. Whether a particular lever action feeds the shorter .38 Special round reliably is model-specific.
Owning a .357 Magnum firearm therefore gives access to both cartridges; owning a .38 Special firearm gives access to one.
What is each cartridge commonly used for?
.38 Special is commonly used for:
- Target shooting and practice in both .38 Special and .357 Magnum revolvers
- Concealed carry in lightweight revolvers, where many owners carry .38 Special or +P to keep recoil manageable in a light gun
- Wadcutter target loads for bullseye and short-range paper shooting
.357 Magnum is commonly used for:
- Revolver hunting of medium game where state regulations allow handgun cartridges of this class
- Outdoor carry, where heavier bullets at Magnum velocity are the reason for the cartridge
- Lever-action carbines that share ammunition with a revolver
Criteria a reader can apply to their own situation:
- Gun weight. A lighter revolver turns the same momentum into sharper recoil; the ratios above scale directly with it.
- Practice volume. Many .357 Magnum owners practice with .38 Special because it is the lower-pressure, lower-recoil round that fits the same chambers.
- Whether the higher velocity is used. If a task does not need the Magnum's additional velocity, a .38 Special load fired from the same revolver remains available.
- Rifle sharing. A .357 lever action and a .357 revolver use the same ammunition supply.
How does cost compare?
Ammunition pricing changes daily and differs by retailer, so this article quotes no figures. Several structural factors affect it: .38 Special is loaded with less powder and is widely offered in lead-bullet practice loads, while .357 Magnum is more often offered in jacketed bullets and smaller box counts. Current observed cost per round for both is on the .38 Special ammo prices and .357 Magnum ammo prices pages, and the observed trend over time is on .38 Special price history and .357 Magnum price history.
Related comparisons
- 9mm vs .38 Special — Semi-auto against revolver at similar energy
- 9mm vs .357 Magnum — Capacity against per-round energy
- What is +P ammo? — Pressure ratings and how +P is marked
Related caliber pages
- .38 Special ammo prices — Current pricing across tracked retailers
- .38 Special price history — Observed trend over time
- .357 Magnum ammo prices — Current pricing across tracked retailers
- .357 Magnum price history — Observed trend over time
- .38 Special vs .357 Magnum side by side — Specifications with live pricing
Sources
- SAAMI Cartridge & Chamber Drawings — Dimensions and maximum average pressure for .38 Special, .38 Special +P, and .357 Magnum
- C.I.P. TDCC tables — CIP maximum pressure for .357 Magnum
- Federal Premium — American Eagle AE38K and AE357A, and 357B published velocity and energy
- Winchester Ammunition — Super-X X38S1P published velocity and energy