.38 Special vs. .38 S&W: What’s the Difference and Are They Interchangeable?
If you’re comparing .38 Special vs. .38 S&W, the first thing to know is that these are two different revolver cartridges. Despite their nearly identical names, they have different case dimensions, bullet diameters, operating pressures, and ballistic performance. Most importantly, .38 Special and .38 S&W ammunition should not be treated as interchangeable.
The confusion is understandable because both cartridges trace their history to Smith & Wesson and carry the “.38” designation. But the similarities largely end there. The .38 S&W is the older, shorter cartridge, while the .38 Special was introduced later with a longer case and greater performance potential.
If you’re trying to identify which ammunition belongs in a particular revolver, always use the cartridge designation stamped on the firearm and follow the manufacturer’s specifications rather than relying on the similar names.
.38 Special vs. .38 S&W at a Glance
| Feature | .38 Special | .38 S&W |
|---|---|---|
| Introduced | 1898 | 1877 |
| Typical firearm | Revolvers | Older revolvers, especially top-break designs |
| Case length | 1.155″ | 0.775″ |
| Overall cartridge length | 1.550″ | 1.240″ |
| Bullet diameter | Approximately .357″ | Approximately .361″ |
| SAAMI maximum pressure | 17,500 psi | 14,500 psi |
| Typical bullet weights | 110–158 grains | Approximately 145–146 grains in many modern loads |
| Modern availability | Very widely available | Much more limited |
| Interchangeable? | No | No |
The dimensional differences are significant. The .38 S&W has a shorter, slightly wider case and uses a larger-diameter projectile than .38 Special.
Is .38 S&W the Same as .38 Special?
No. .38 S&W and .38 Special are not the same cartridge.
This is one of the most important distinctions to understand.
The full name “.38 Smith & Wesson Special” is an alternate name associated with .38 Special, which can add to the confusion. The shorter .38 Smith & Wesson, commonly abbreviated .38 S&W, is an entirely different cartridge.
The .38 S&W was introduced in 1877, while the .38 Special followed in 1898. The later .38 Special uses a substantially longer case and became one of America’s most widely used revolver cartridges.
Why Are Both Called “.38”?
Cartridge names don’t always correspond exactly to modern bullet measurements.
The “.38” designation is rooted in the historical naming conventions used when these cartridges were developed. Consequently, two cartridges carrying a “.38” name can have different actual bullet and case dimensions.
That’s exactly what happened with .38 S&W and .38 Special.
.38 Special vs. .38 S&W Dimensions
The easiest way to understand the difference is to compare the cartridges dimensionally.
.38 Special
The .38 Special has a 1.155-inch case and an overall cartridge length of approximately 1.550 inches. Its bullet diameter is approximately .357 inch.
Its longer case provides considerably more internal capacity than .38 S&W and allows the cartridge to accommodate a broader range of modern factory loads.
.38 S&W
The .38 S&W has a much shorter 0.775-inch case and approximately 1.240-inch overall length. Its bullet diameter is approximately .361 inch.
That difference may not sound dramatic on paper, but it matters when determining which cartridge a revolver is designed to fire.
Are .38 Special and .38 S&W Interchangeable?
No. Do not interchange them.
Although the cartridges share a similar name and both are rimmed revolver cartridges, their dimensions and pressure specifications are different. A firearm chambered for one should be loaded only with ammunition specifically designated for that chambering.
This is especially important with older revolvers. Many .38 S&W firearms are vintage or historical guns, and their condition, chamber dimensions, and mechanical strength may differ substantially from those of modern revolvers.
If you’re unsure what an older revolver is chambered for, don’t test different .38 cartridges to see what fits. Check the firearm markings and consult the manufacturer’s documentation or a qualified gunsmith.
Can You Shoot .38 Special in a .38 S&W Revolver?
Not simply because it fits.
There are historical and modified firearms that can create confusing exceptions. Some older .38 S&W revolvers have been altered or re-chambered, which is one reason anecdotal reports about interchangeability can be misleading.
A cartridge fitting into a chamber does not automatically mean the firearm is designed to safely fire it.
This distinction is particularly important with vintage revolvers. If the markings are unclear or the firearm has an unusual history, have the chambering verified by a qualified professional before selecting ammunition.
.38 Special vs. .38 S&W Ballistics
The .38 Special generally has a substantial ballistic advantage over .38 S&W because of its larger case capacity and higher pressure specification.
Factory ammunition varies considerably, so there isn’t one universal velocity or energy figure for either cartridge. Barrel length, bullet weight, projectile design, and specific ammunition load all affect real-world performance.
Typical .38 Special factory loads span a broad range of bullet weights, commonly from approximately 110 to 158 grains. .38 S&W ammunition is generally available with heavier, slower-moving bullets, with 145–146 grain loads being common examples.
Example Factory Ballistics
| Cartridge | Example Bullet | Muzzle Velocity | Muzzle Energy |
|---|---|---|---|
| .38 Special | 110 gr FTX | 1,010 fps | 249 ft-lbs |
| .38 Special | 125 gr XTP | 900 fps | 225 ft-lbs |
| .38 Special | 158 gr LRN | 997 fps | 349 ft-lbs |
| .38 S&W | 145 gr LRN | 689 fps | 153 ft-lbs |
| .38 S&W | 146 gr LRN | 685 fps | 152 ft-lbs |
These figures illustrate the general performance gap, but advertised factory ballistics aren’t guaranteed to match what you’ll see from your particular firearm. Barrel length and ammunition lot can change actual velocity and energy.
Which Has More Power: .38 Special or .38 S&W?
Generally, .38 Special.
The .38 Special was developed as a longer and more capable cartridge, while .38 S&W originated much earlier as a lower-pressure revolver cartridge.
Modern .38 Special ammunition is also available in a much wider variety of bullet designs and performance levels, including target loads, standard-pressure defensive loads, and +P ammunition for firearms specifically rated for it.
That doesn’t make every .38 Special load automatically superior for every purpose. The correct ammunition still depends on the firearm and intended application.
.38 Special vs. .38 S&W: Which Is More Common?
There’s a significant difference in ammunition availability.
.38 Special is vastly more common today. It remains a mainstream revolver cartridge with broad support from ammunition manufacturers and a large selection of bullet weights and designs.
.38 S&W is considerably more niche. It continues to be produced, but its primary market consists of owners of older and historical firearms chambered for the cartridge.
That distinction matters if you’re shopping for ammunition. A modern .38 Special revolver gives you many more factory ammunition choices than an older .38 S&W revolver.
Why Is .38 S&W Still Available?
The .38 S&W may be an old cartridge, but there are still plenty of historical firearms chambered for it.
The cartridge has an especially interesting history because variants were used in British and Commonwealth service revolvers. The British military adopted a .38 S&W-based cartridge commonly known as .38/200, which was used in service revolvers during the 20th century.
That historical connection is one reason collectors and owners of vintage revolvers continue to seek out .38 S&W ammunition.
For these shooters, the cartridge isn’t competing directly with 9mm or modern defensive handgun cartridges. It’s ammunition for a specific class of historical firearms.
.38 S&W vs. .38 Special for Self-Defense
For a modern revolver specifically chambered in .38 Special, the cartridge offers a much broader selection of purpose-designed factory ammunition.
The .38 S&W, by comparison, is primarily associated with older firearms and comparatively modest ballistic performance.
That doesn’t mean someone should automatically attempt to modernize an older .38 S&W revolver by using a different cartridge. The firearm’s original chambering should always dictate ammunition selection.
For vintage firearms, correct chambering and firearm condition come before ballistic performance.
How to Tell Which .38 Cartridge You Have
The safest starting point is the marking on the firearm.
Look for the caliber designation stamped on the barrel or frame. Depending on the firearm, you may see markings such as:
- .38 S&W
- .38 Smith & Wesson
- .38 Special
- .38 S&W Special
Be particularly careful with “.38 S&W Special.” That designation refers to .38 Special rather than the shorter .38 S&W cartridge.
If the markings are worn, missing, or difficult to interpret, don’t rely on cartridge appearance alone. Have the firearm identified by a qualified gunsmith or other competent professional.
.38 Special vs. .38 S&W: Key Differences
Here’s the simplest way to remember the comparison:
.38 Special
- Longer case
- Approximately .357″ bullet diameter
- Higher pressure specification
- Greater range of modern factory ammunition
- Extremely common revolver cartridge
- Available in numerous bullet weights and designs
.38 S&W
- Shorter case
- Approximately .361″ bullet diameter
- Lower pressure specification
- Much less common ammunition
- Primarily associated with older revolvers
- Important historical and collector cartridge
Frequently Asked Questions
Is .38 S&W the same as .38 Special?
No. They are separate cartridges with different case dimensions, bullet diameters, pressure specifications, and ballistic characteristics.
Can you shoot .38 S&W in a .38 Special revolver?
No. They are not interchangeable. Use only the ammunition designation specified for the firearm.
Can you shoot .38 Special in a .38 S&W revolver?
Do not assume that you can. Even if a cartridge appears to fit a particular firearm, that does not establish that the firearm is chambered or rated for it. Older revolvers require particular caution.
Why is .38 S&W called .38?
The “.38” designation comes from historical cartridge-naming conventions and does not mean that .38 S&W and .38 Special use identical bullet dimensions.
Which is more powerful, .38 Special or .38 S&W?
Generally, .38 Special. Its longer case and higher pressure specification allow modern .38 Special ammunition to deliver substantially greater velocity and energy than typical .38 S&W loads.
Is .38 S&W still available?
Yes. Although considerably less common than .38 Special, .38 S&W ammunition is still manufactured for owners of compatible vintage and historical firearms.
Is .38 S&W the same as .38 S&W Special?
No. This is an especially important naming distinction. “.38 S&W Special” refers to .38 Special, while “.38 S&W” refers to the older, shorter Smith & Wesson cartridge.
Final Verdict: .38 Special vs. .38 S&W
The .38 Special and .38 S&W are not the same cartridge, despite their confusingly similar names.
The .38 S&W is the older and shorter cartridge, with a slightly larger bullet diameter and lower pressure specification. The .38 Special arrived later with a longer case, greater ballistic potential, and a much broader selection of modern ammunition.
For ammunition shopping, the takeaway is simple: buy the cartridge that exactly matches the chambering marked on your firearm. Don’t use the fact that another .38 cartridge appears similar or may physically fit as a substitute for verifying the correct ammunition.
If you’re shopping for .38 Special ammunition, its enormous selection and continued popularity make it one of the easiest classic revolver cartridges to find. If you own a vintage firearm chambered in .38 S&W, look specifically for .38 S&W ammunition and verify the condition and chambering of the firearm before shooting it.
The similar names may cause the confusion, but once you compare the dimensions, history, pressure, and intended firearms, the distinction between .38 Special vs. .38 S&W becomes clear.