357 Magnum vs 38 Special

Banana Ballistics • October 31, 2023

If you have been around firearms for any amount of time, chances are, you have probably fired a 38 special and/or a 357 magnum. Although they are very similar cartridges physically, the 38 special and the 357 magnum offer very different capabilities, making for a tricky decision. In this article, we will be discussing some of these similarities and differences to help make your choice a little easier.

Physical Attributes

As different as the naming may be, the 38 special and the 357 magnum share more in common than you may think. To start, both cartridges utilize the same 0357” diameter projectiles, though weight ranges are generally not the same. 38 special loads typically stay between 120 – 158 grains, while 357 magnum loads extend this range all the way up to 200 grain projectiles in some cases.

Along with the use of the same projectiles, both cartridges are almost exclusively chambered in revolvers. Being designed around revolvers, both cartridges utilize a rimmed design with the same rim diameter of 0.440 inches as well as the same body diameter of 0.379 inches.

In fact, they share these case dimensions because the 38 special is the parent case of the 357 magnum. This means that the 357 magnum case is essentially a lengthened version of a 38 special case. Placed side by side, this additional length is evident. With a nominal empty case height of 1.29 inches, the 357 magnum towers over the 38 special’s nominal case length of 1.155 inches.

Due to the additional length of the 357 magnum as well as the shared case dimensions, revolvers and lever actions cut with a 357 chambering also have the ability to fire the 38 special (not vice versa). As you can imagine, this additional length equates to a difference in performance between these cartridges as well.

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Power

When it comes to power, the 38 special and the 357 magnum are two very different cartridges. Other than length, the biggest difference between these cartridges is the pressures that they are operating at. SAAMI lists the 357 magnum as having a maximum pressure of 35,000 psi, or exactly double that of a standard 38 special (maximum pressure of 17,500 psi).

It’s not hard to imagine that this massive increase in pressure gives the 357 magnum a distinct advantage when it comes to power. In general, standard 357 magnum loads produce somewhere between 500-600 ft/lbs. of energy at the muzzle (can be slightly less), with max loads sometimes exceeding 800 ft/lbs. (some approaching 900) at the muzzle.

By comparison, conventional 38 special loads produce somewhere between 150-250 ft/lbs. of energy at the muzzle, or about one third the power of the 357 magnum. Though these figures don’t even reach 9mm territory, the modern 38 special has a trick up its sleeve to increase performance.

If your firearm is rated for it, 38 special has a +P loading designation* that increases its standard maximum pressure rating of 17,500 psi up to 20,000 psi. With this increase in pressure, 38 special +P loads increase power up to around 350-400 ft/lbs. of energy at the muzzle, or right around standard 9mm figures.

Loads such as the Underwood Ammo 38 Special +P 158 Grain Hard Cast, can far exceed this range (555 ft/lbs. at a muzzle velocity of 1,250 feet per second) though this is not typically the case. Even with these load ratings however, the 38 special does not come anywhere near the power of top performing 357 magnum loads.

Recoil

While the 38 special is not producing anywhere close to the power of the 357 magnum (with conventional loads), it is not producing anywhere near the amount of recoil either. Assuming that both cartridges are fired out of a 45.3 ounce (2.83 pounds) 6-inch Smith and Wesson Model 686, the difference is substantial.

Looking at Federal’s American Eagle 38 Special 130 grain FMJ load, we see that it produces approximately 2 ft/lbs. of felt recoil out of the test handgun. With Federal’s American Eagle 357 Magnum 158 grain JSP, we see that it generates around 6 ft/lbs. of felt recoil from the same handgun.

While there is a noticeable difference between the 38 special and the 357 magnum in the field, neither one of these cartridges is known for having excessive recoil (at least out of full-size revolvers). Perhaps the most noticeable difference when firing these cartridges is muzzle blast.

Due to the low pressure and low velocities (usually subsonic) of the 38 special, its muzzle report can often be described as mild, or the complete opposite of the 357 magnum. With its much higher pressure and velocities (usually supersonic), the 357 magnum has a muzzle blast that is almost exclusively described as excessive. As barrel length decreases, this becomes even more noticeable.

To some, this may be a detracting factor of the 357 magnum, especially when new shooters are present. It is important to remember, however, that 357 magnum chambered revolvers can also fire the 38 special. This allows shooters to switch to 38 special loads if the 357 magnum is too much to handle.

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Why 38 Special?

Considering that 357 magnum chambered revolvers can also fire the 38 special, it would seem pointless to buy a revolver chambered specifically in 38 special, right? While 357 magnum chambered revolvers are far more versatile than 38 special counterparts, there is one primary factor as to why 38 special revolvers are still a popular option…. Concealability.

Although revolvers do not compete with the capacity of modern compact semi auto handguns, they are still a very popular option for concealed carry. When it comes to concealable revolvers, the 38 special has become one of the most popular chamberings due to a large number of options that feature very small profiles.

Models such as the Smith and Wesson 642, 442, and 638 offer some of the smallest revolver profiles currently available at reasonable prices (in terms of revolvers). It should be noted however, that these small profiles are generally very lightweight, often weighing less than 1 pound. Although limited weight may be a good feature for a carry weapon, it also increases felt recoil, though it is usually manageable with conventional 38 special loads. 

While there are nowhere near the number of options when it comes to ultra compact 357 magnum revolvers, they do exist and can be very enticing. The Smith and Wesson 340 PD for example, offers a very similar profile to the smallest 38 special revolvers, with the added benefit of being able to fire 357 magnum loads.

At a mere 11.8 ounces, it is also one of the lightest carry revolvers on the market, though recoil can be excessive with full power 357 magnum loads. If, however, you can handle the extra recoil as well as the much higher price tag (compared to many 38 special models), the 340 PD’s added benefit of being able to fire the 357 magnum may have you think twice about a 38 special specific revolver.

Conclusion

Although the 38 special and the 357 magnum are very similar cartridges physically, they offer very different capabilities overall. So, the question becomes, which one should I choose?

With the various number of ultra compact revolvers chambered in the 38 special, the cartridge makes a lot of sense for those wishing to carry a revolver. With an often-limited recoil and muzzle report, the 38 special also makes for a great cartridge to teach new shooters as well as high volume target shooters.

Although the 357 produces more recoil and muzzle blast than the 38 special, it produces nearly 3 times the power with conventional loads. Perhaps the biggest advantage of 357 magnum chambered revolvers and lever actions, however, is their ability to fire the 38 special as well. This gives shooters the benefits of the 38 special while also having the option to fire much more powerful 357 magnum loads when desired.

Regardless of the route you choose to go, the 38 special and the 357 magnum have long been among the most popular revolver cartridges with no signs of slowing down.

*Always verify that your firearm is rated for the specific ammo that you intend to use.

--Banana Ballistics