38 S&W vs 38 Special: The Confusing Caliber Names
Few caliber naming situations in the firearms world cause as much genuine confusion – and potential danger – as the 38 S&W versus the 38 Special. Both names start with "38," both come from Smith and Wesson’s history, and both fire bullets that look similar at a glance. But they are not the same cartridge, they are not interchangeable, and using one in a firearm chambered for the other can get you seriously hurt.
This article breaks down exactly what separates these two rounds, how to identify which one your revolver actually uses, and why getting this right matters more than most caliber mix-ups. Whether you inherited a Webley, picked up a Victory revolver at an estate sale, or are just sorting out your ammunition shelf, this guide gives you the straight answers.
The Origins of Two Very Different 38 Calibers
The 38 S&W cartridge came first, introduced in 1877. Smith and Wesson developed it for their small top-break revolvers, and it became widely adopted across law enforcement and military circles – particularly in Britain. The British military used it extensively through both World Wars, chambering it in Webley revolvers and later in the Smith and Wesson Victory revolver supplied through Lend-Lease.
The 38 Special arrived in 1902, also from Smith and Wesson, but it was a completely different design built for higher performance. It was engineered to replace the 38 Long Colt in U.S. military and law enforcement service. Despite sharing "38" in the name and the S&W heritage, the two cartridges have different case dimensions, different bullet diameters, and very different pressure ratings.
38 S&W Basics – Bullet Diameter and Pressure
Physical Specs
The 38 S&W fires a bullet with a diameter of 0.361 inches, though some older loads and foreign military loadings pushed that up to 0.386 inches in heeled-bullet configurations. The case is relatively short and fat compared to the 38 Special. Standard operating pressure for 38 S&W sits around 14,500 PSI – significantly lower than modern cartridge standards.
That lower pressure is not a flaw. It was intentional, designed for the older top-break revolvers and swing-out cylinder guns of the era, which were not built to handle high-pressure loads. The round was adequate for its intended purpose, but it was never a high-velocity performer. Typical factory loads push a 145-grain bullet to around 685 feet per second.
Availability Today
- 38 S&W ammunition is limited – you will not find it at most big box stores
- Specialty retailers and online sources carry it, but expect to pay more per box
- Some European and British surplus loads still surface occasionally
- Reloading components exist but are less common than for 38 Special
- If you own a 38 S&W firearm, stock up when you find ammunition
38 Special Specs – The Modern Revolver Standard
The 38 Special fires a bullet with a nominal diameter of 0.357 inches, though loaded rounds can measure up to 0.379 inches depending on the jacketing and design. The case is noticeably longer and slimmer than the 38 S&W case. Standard pressure runs around 17,000 PSI, with +P loads pushing up to 20,000 PSI.
This is the cartridge you find everywhere today. It is one of the most common revolver calibers in North America, used for self-defense, target shooting, and training. Virtually every major ammunition manufacturer produces it in dozens of load configurations. If you walk into any gun store in the U.S. or Canada, you will find 38 Special on the shelf.
Why It Became the Standard
- Accurate and manageable recoil for most shooters
- Wide range of bullet weights – from 110 to 158 grains commonly available
- Compatible revolvers are abundant and affordable
- 357 Magnum revolvers can also fire 38 Special safely (not vice versa)
- Excellent support for handloaders with widely available components
Key Dimensional Differences Between Both Rounds
Here is a compact comparison of the critical specs:
| Spec | 38 S&W | 38 Special |
|---|---|---|
| Bullet Diameter | 0.361 in | 0.357 in |
| Case Length | 0.775 in | 1.155 in |
| Overall Length | 1.240 in | 1.550 in |
| Max Pressure | ~14,500 PSI | ~17,000 PSI |
| Typical Bullet Weight | 145 gr | 110-158 gr |
The case length difference is the most immediately obvious distinction. A 38 Special case is roughly 0.38 inches longer than a 38 S&W case. This is actually why a 38 Special cartridge will sometimes physically fit into a 38 S&W cylinder – the chamber is wider, and the longer case can partially seat. That partial fit is exactly what makes this dangerous.
Why Mixing These Calibers Is Dangerous
38 Special in a 38 S&W Firearm
This is the scenario that gets people hurt. The 38 Special case is longer than the 38 S&W chamber, but because the chamber mouth is wider, the round can sometimes be forced in or partially chamber. When fired, the unsupported case can rupture, sending hot gas and debris back toward the shooter. The higher pressure of the 38 Special also exceeds what older 38 S&W revolvers – especially Webleys – were designed to handle.
Do not do this. Not even once. Not even to see if it fits. The risk is real and the outcome can be catastrophic.
38 S&W in a 38 Special Firearm
This direction is less immediately dangerous but still a problem. The 38 S&W bullet is wider than the 38 Special bore. Forcing an oversized bullet down a tighter barrel creates excessive pressure and will produce terrible accuracy. In some cases it can also damage the firearm. Even if the round technically fires, you are not shooting safely or accurately.
Common Mistakes With 38 S&W and 38 Special
These are the errors that come up most often with these two calibers:
- Buying by name alone – seeing "38" and assuming all 38-caliber revolver ammo is the same
- Inheriting a firearm without checking the barrel marking – old guns often have worn or faded markings
- Assuming a British or WWII-era revolver takes 38 Special – many do not
- Using 38 S&W in a 38 Special revolver for "softer recoil" – this is unsafe and inaccurate
- Trusting the previous owner’s word without verifying the actual chamber specs
- Ignoring headstamp markings on surplus ammunition – military headstamps can be cryptic
- Skipping the cylinder gauge check when restoring or buying a used revolver
If you are unsure what caliber your revolver is chambered for, take it to a qualified gunsmith before you run any ammunition through it. This is not a situation where guessing is acceptable.
Identifying Your Platform – Webley, Victory, or S&W
Webley Revolvers
Webley revolvers – particularly the Webley Mk IV and Mk VI – are chambered in 38 S&W, often referred to in British service as the "38/200" because of the 200-grain bullet used in early military loadings. These are top-break designs with a distinctive profile. If you have one, it takes 38 S&W, period. Many were imported to the U.S. and Canada after WWII, and some are still floating around in collections and estates.
S&W Victory Revolvers
The Smith and Wesson Victory revolver is a common source of confusion. These were produced for the British military during WWII under Lend-Lease and were chambered in 38 S&W – not 38 Special. However, Victory revolvers were also produced for U.S. military use, and those were often chambered in 38 Special. The barrel marking is your definitive answer. Look for "38 S&W" or "38 Special" stamped on the barrel – do not assume based on appearance alone.
Quick Checklist – Identifying Your Revolver’s Caliber
- Check the barrel for a caliber stamp (usually on the left side near the frame)
- Check the cylinder face for any markings
- Look inside the cylinder with a chamber gauge or have a gunsmith measure it
- Check any original documentation, import markings, or proof marks
- Research the model and serial number range to confirm original chambering
- If the markings are worn, do not guess – get it professionally verified
- Never rely solely on what the seller or previous owner said
FAQ – 38 S&W vs 38 Special Answered
Q: Can I shoot 38 Special in a Webley revolver?
A: No. Webley revolvers are chambered in 38 S&W. Shooting 38 Special in them risks case rupture and exceeds the pressure limits the gun was designed for. Use only 38 S&W ammunition.
Q: Is 38 S&W the same as 38 Smith and Wesson?
A: Yes. "38 S&W" and "38 Smith and Wesson" are the same cartridge. Some older boxes and headstamps may also label it as "38 S&W Special" which causes further confusion – but that phrasing typically refers to 38 Special, not 38 S&W.
Q: Why do both calibers have "38" in the name if they are different?
A: The "38" refers loosely to the bore diameter in both cases, but the measurement conventions used when these cartridges were developed were not precise by modern standards. The naming has more to do with marketing and lineage than strict dimensional accuracy.
Q: Is 38 S&W ammunition still being made?
A: Yes, but in limited quantities. Fiocchi and a handful of other manufacturers still produce it. It is more expensive and harder to find than 38 Special. If you own a 38 S&W firearm, buying in bulk when you find it is a practical approach.
Q: Can I shoot 38 S&W in a 38 Special revolver?
A: You should not. The bullet diameter is larger than the bore of a 38 Special barrel, which creates accuracy problems and unsafe pressure levels. Even if the round chambers, firing it is not recommended.
Q: How do I know if my Victory revolver takes 38 S&W or 38 Special?
A: Check the barrel stamp. U.S. military Victory revolvers were typically chambered in 38 Special. British contract Victory revolvers were chambered in 38 S&W. The barrel marking is the only reliable confirmation – serial number ranges and production records can also help narrow it down if the markings are worn.
Quick Takeaways
- 38 S&W and 38 Special are not interchangeable – treat them as completely different cartridges
- The 38 S&W has a wider bullet (0.361 in) and lower pressure than the 38 Special (0.357 in)
- Shooting 38 Special in a 38 S&W firearm is genuinely dangerous
- Webley revolvers and British-contract Victory revolvers use 38 S&W
- Always verify your revolver’s caliber from the barrel stamp, not assumptions
- 38 S&W ammunition is available but limited – plan accordingly if you own one
- When in doubt, have a qualified gunsmith verify the chamber before shooting
