Compared: The .380 ACP and .38 Special
By Chuck Hawks
The .38 Special and .380 ACP have long been among the most popular self-defense and police service cartridges in the world. The .38 Special's nomenclature is simple enough, but the .380 is blessed with an overabundance of names, particularly overseas. This little cartridge, and the guns chambered for it, may be marked .380 ACP or .380 Auto, which is the American designation. In Europe and other parts of the world, the .380 is also known as the 9x17mm, 9mm Kurz, 9mm Browning Short, 9mm Corto and variations of these. For example, a couple of weeks before I began this article we reviewed two brand new SIG SAUER .380 pistols. One, a model P238 made in the USA, was marked ".380 Auto." The other, a model P232 made in Germany, was marked "9mm Kurz." This can be confusing to the uninitiated!
The .38 Special is perhaps the best known of all revolver cartridges. It was developed in 1902 as a ballistic improvement over the .38 Long Colt and it became a very popular and successful police service cartridge in North and South America, chambered in large numbers of Colt, S&W and Ruger service revolvers. It was not surpassed in popularity as a police service cartridge until the last quarter of the 20th Century. The .380, introduced in 1908, served much the same role in Europe. Although offered in a great number of pistols, perhaps the .380's most famous and enduring home has been the Walther PP series pistols, the first successful double action autoloaders. ("PP" stands for "police pistol.")
Both the .38 Special and the .380 have also served in various places, times and services as military cartridges. The 9mm Kurz, for example, served as a substitute standard pistol cartridge all across German occupied Europe during World War II and, in the PP and PPK pistols, was especially popular with Luftwaffe aircrews. The U.S. Air Force favored the .38 revolver and when I was in the USAF in the late 1960's, the .38 revolver was the standard service sidearm of the Air Police. These two cartridges remain very popular for civilian self-defense, which is the role that primarily concerns most Guns and Shooting Online readers.
It makes sense that any cartridge that has enjoyed so much popularity for so long must have something going for it. Many Colt, Rossi, Ruger, Taurus and S&W revolvers on large, medium and small frames have been offered in .38 Special, along with derringers, rifles and even semi-automatic target pistols. It is the small frame revolver, however, that is most popular for civilian concealed carry and personal defense.
Similarly, many medium and small frame semi-automatic pistols have been offered in .380, along with a few sub-machine guns. The small frame autoloaders are most popular for civilian concealed carry and personal protection. Most shooters, for example, are familiar with .380 pistols from Beretta, Bersa, Browning, Colt, Kel-Tec, SIG-SAUER and Walther.
The .38 Special uses a long, rimmed, straight case that is typical of revolver cartridges. The .38 Special case is 1.155" long with a base diameter of .379" and accepts .357" diameter bullets. The typical factory loaded range of bullet weights runs from about 95 to 200 grains. The SAAMI maximum average pressure (MAP) for the standard .38 Special has been reduced to only 17,000 psi. The MAP for .38 Special +P loads is a modest 20,000 psi. This is below the pressure of the High Speed factory loads offered from the 1930's well into the 1970's for strong .38 Special revolvers. Those loads offered a 158 grain bullet at a muzzle velocity (MV) of 1090 fps with muzzle energy (ME) of 425 ft. lbs.
The .380 ACP uses a much shorter rimless case. This case is .680" long with a base diameter of .374" and accepts .355" diameter bullets. The typical range of factory loaded bullet weights extends from about 85 to 102 grains. Because the .380 was designed specifically to be the most powerful cartridge practical for use in blow-back actions (which are simpler than locked breech actions), the SAAMI MAP for the .380 is held to 21,500 psi.
Both the .380 ACP and .38 Special are primarily self-defense handgun cartridges and that is the way we will compare them. For each cartridge I am going to select one typical and widely available type of factory load, the ballistics of which are easy to compare.
Our representative .38 Special +P load will be a 125 grain JHP bullet at a muzzle velocity of 945 fps and muzzle energy of 248 ft. lbs. At 50 yards, the figures are 898 fps and 224 ft. lbs. These are Remington figures, measured in a 4" vented (revolver) barrel, but the figures for Hornady, Winchester, Federal, et al are essentially identical.
Our representative .380 ACP load will use a 90 grain JHP bullet at a MV of 1000 fps and ME of 200 ft. lbs. At 50 yards, the numbers are 910 fps and 165 ft. lbs. These are Federal figures measured in a 3.75" (closed breech--not vented) barrel, but the other major brands are similar.
Since the .380 and .38 Special are actually .35 caliber cartridges and use bullets of approximately the same diameter, bullet frontal area will play no part in this comparison. Trajectory is not usually of primary importance for civilian self-defense and, in any case, there is no practical difference between these .38 Special and .380 ACP loads over 50 yards. They have a 50 yard mid-range trajectory of 1.2-1.3 inches. This leaves recoil, velocity, kinetic energy, sectional density and stopping power as the critical factors in our comparison.
Lighter recoil tends to make for more comfortable and accurate shooting. The lighter the recoil, the faster a shooter can get back on target for quick follow-up shots. Moderate recoil is one of the reasons for the popularity of these cartridges. Another reason is their (relatively) mild muzzle blast. A huge bang and flash of light is disconcerting to shooters, especially at night. The .380 and .38 Special avoid both.
Important as it is, recoil can almost be dispensed with in this comparison. A quick perusal of the "Handgun Recoil Table" on the Tables, Charts and Lists page shows that the recoil energy of both of these cartridges runs between about 2-1/2 and 5-1/5 foot pounds with typical self-defense loads, depending on the pistol weight and specific load compared. Neither can be considered a hard kicking handgun cartridge in pistols of normal weight and, in practical terms, one is about as controllable as the other when multiple shots are required.
Velocity is important for initiating bullet expansion and it is the most important factor in calculating kinetic energy. The .380 has the advantage in velocity from the muzzle to 50 yards, due largely to its lighter weight bullet. At the muzzle, its advantage amounts to 55 fps, which has decreased to zero at 50 yards, where both of our comparison bullets are traveling at 910 fps.
Kinetic energy is defined as the ability to do work. In this case, the "work" involved is primarily powering bullet penetration and expansion. The .38's heavier bullet gives it more kinetic energy. At the muzzle, the .38 has a 48 ft. lb. advantage. At 50 yards, the 125 grain .38's advantage has increased to 59 ft. lbs.
Sectional Density (SD) is the ratio of a bullet's weight (in pounds) to its diameter squared (in inches). SD is important when comparing cartridges and loads because, other factors (such as impact velocity and bullet design) being equal, the bullet with the greatest SD will penetrate deeper. The sectional density of a 90 grain, .355" diameter bullet is .102. The SD of a 125 grain, .357" bullet is .140. Neither is an impressive number, but it is clear that the .38/125 has a significant advantage in SD.
Never forget that bullet placement is the most important factor in stopping power. Moving beyond bullet placement, we do not need to resort to arcane formulas to estimate the stopping power of common handgun cartridges. In our society, the police are required to fill out detailed reports when someone is shot. Evan Marshall and Edwin Sanow analyzed thousands of police reports of shootings involving all of the popular handgun calibers and hundreds of individual loads and published the results. In compiling their statistics, they considered only single bullet hits to the torso. Shootings where the victim received multiple hits, or where the bullet was stopped short by an obstacle or soft armor, were excluded. They defined incapacitation (stopping power) as the inability to perform hostile acts, whether armed or unarmed, toward anyone, even if determined to do so; if fleeing, the perpetrator collapsed within 10 feet.
Their seminal research on handgun stopping power revealed that in .380 ACP the Federal 90 grain JHP factory load delivered about 65% one shot stops. The popular .38 Special 125 grain JHP loads from several manufacturers (including Federal) delivered between 63-69% one shot stops. We can conclude that, given bullets of similar performance, there is little difference in stopping power between the two cartridges.
These were mostly frontal shooting situations, the most common kind. If some sort of barrier had to be penetrated to reach the perpetrator, the .38's advantage in SD would probably make it at least marginally more effective. Neither the .38/125 grain or .380/90 grain loads are noted for deep penetration, however.
Summary, Comments and Conclusion
To recap what we have learned, both cartridges are very popular and offer a large assortment of factory loaded ammunition. Either, with good JHP factory loads, will deliver in the neighborhood of 65% one shot stops on human predators. There is no shortage of guns in either caliber, although the revolver shooter will likely choose the .38 Special and the semi-automatic pistol fan will likely choose the .380.
For use in the field as a plinking, target, or hunting pistol cartridge, the .38 Special has the advantage. This is partly due to its greater range of bullet weights and velocities and partly due to the fine target revolvers available in the caliber, which are more suitable for field use than most autoloading pistols. As protection against dangerous animals for campers, fishermen and hikers, full power .38 Special +P loads using the heaviest bullets available in the caliber (158-200 grains) offer superior penetration and presumably killing power to anything available in .380 ACP, where useful bullet weights max out at about 100-102 grains.
Both cartridges are suitable for reloading, but the .38 Special has the edge in load flexibility. For reloaders, revolvers are inherently more convenient and forgiving than semi-automatic pistols and the little .380 case can be clumsy to handle.
One should conclude from this comparison that the .38 Special and .380 ACP are both useful handgun cartridges that have survived the test of time. They are appropriately and widely used for concealed carry and personal defense. Choosing between the two will probably come down to a preference for either the revolver or the autoloading pistol.
Copyright 2010, 2013 by Chuck Hawks. All rights reserved.