October 01, 2021
By Michelle Hamilton, Field Editor
The .380 Automatic Colt Pistol, more commonly known as: .380 Auto, 9x17mm, 9mm Kurz, 9mm Browning Short or simply "380" is a cartridge designed by John Moses Browning and introduced in 1908. It utilizes a .355-inch projectile, which is typically lighter in weight than used in the longer 9mm Parabellum. The .380 Auto is a cartridge with more than 100 years of service and lineage behind it and to this day proves to be not only a popular carry option for self-defense but also for recreational shooting. Hugely popular here in the United States, it also remains popular in Europe and around the globe.
With such a lineage, how does the .380 ACP really rank in terms of modern defensive carry? Is it still a cartridge to consider, especially with micro 9mm handguns like the SIG P365, Ruger MAX-9, Springfield Armory Hellcat and others in existence? Does the .380 ACP possess the terminal performance and penetration to consider it over other cartridges? Do modern expanding loads improve the terminal performance of the .380 ACP to a significant degree? Or is the .380 ACP simply an aging under-powered cartridge from the early 20th Century with better options available? Pondering this question, I decided to examine the .380 Auto from a terminal ballistics standpoint while also considering its practical applications in a modern self-defense scenario.
The .380 Auto gains its name by measuring the exterior diameter of the loaded cartridge (.379-inch), much like the popular .38 Special (which I covered recently HERE). Unlike his earlier semi-rimmed .32 ACP, Browning designed the .380 ACP around a modern rimless straight-wall case. Maximum pressure is 21,500 PSI making it well-suited for use in blowback pistols. Base diameter is 0.374-inch, case length is 0.680-inch (17.3mm) and overall length is 0.984-inch. A traditional early factory load consisted of a 95-grain FMJ projectile with a muzzle velocity of 950 fps. Performance of the .380 Auto is a step above the .32 Auto and good enough for it to have seen military use by Italy, Sweden and Czechoslovakia. It saw heavy combat with Italian troops throughout World War II, including on the Eastern Front.
The .355-inch projectile for the .380 typically weighs in at 80 to 105-grains for a traditional lead and copper constructed projectile and between 50 to 65-grains for a solid copper variant. Often times, the lighter copper projectile will fill the same volume as the lead and copper projectile, despite lacking the mass and weight. The reason being is; Lead has a density of 11.342 g/cm³, whereas Copper has a density of 8.96 g/cm³. Muzzle velocity of modern loads typical range between 875 and 1,000 feet per second when fired from a barrel length exceeding 3 inches. This means, sub-compact and micro pistols (which are most popular for concealed carry) will have even lower muzzle velocities across the board. Due to the .380 Auto’s light bullet weight and relatively low velocities projectile choice is of utmost importance when considering a load for personal protection.
Due to its continuing popularity, most ammunition companies offer the .380 Auto, likely in both a practice and self-defense load. Some companies offer very traditional loads while others try to improve its terminal performance as much as possible. As to be expected, each company has their own opinion on how to "improve" this mouse gun cartridge. The .380 Auto, unlike the .38 Special suffers from both low velocity and low projectile weight. Where the .38 Special lacks speed, it can make up for in mass, thus resulting in consistent and uniform penetration to vital organs from varying barrel lengths. The .380 Auto doesn’t have this option.
So, how do you go about improving the terminal performance of the .380 ACP for personal protection? Now, this is where the “ideology” of ammunition companies can differ. Companies will typically go one of three ways when developing a .380 Auto load for personal protection. The first is to simply stay with the traditional bullet weight and velocity as John Moses Browning intended for this cartridge. The second is to use a lightweight projectile pressed to higher velocities not commonly seen with the .380 Auto. The third is to increase bullet weight. All three have their advantages and drawbacks.
The advantage of using a traditional bullet weight and velocity is reliability. This type of load should function well and match the factory sights. The chief shortcoming when it comes to expanding loads intended for personal protection is trying to balance bullet expansion with penetration. If you follow my writing you know I prefer more than the FBI minimum of 12-inches of penetration in properly calibrated 10% Ordnance Gelatin. If a projectile penetrates less than the FBI 12-inch minimum it may not penetrate deeply enough to reach the vital organs of your attacker. Keep in mind, your projectile may have to pass through a light barrier or one of your attacker’s arms (this is surprisingly common) before impacting their torso. With the .380 Auto it’s a balancing act between bullet expansion and penetration. Basically the faster the bullet expands, and the larger the diameter the bullet expands to, the shorter the total amount of penetration will be due to a lack of projectile mass. Unfortunately, a design that expands well will typically fail to meet the FBI 12-inch minimum penetration depth.
When you decrease bullet weight while increasing velocity you typically see impressive projectile expansion but insufficient penetration with the .380 Auto. This stems from the rapid and immediate expansion of the lightweight projectile, which leads to a rapid slowing in mediums (such as 10% ballistic gel) due to the lack of mass vs the rapidly changing frontal area of the projectile, which is (at this point) no longer aerodynamic. Typical penetration depths from loads such as this can run from 7-10 inches in 10% ballistic gel, falling short of the 12-inch minimum FBI protocol.
Another approach is to add projectile weight, which typically reduces muzzle velocity. This will result in substantially deeper penetration, but often times an expanding projectile fails to reliably expand through light barriers (such as the FBI heavy clothing protocol). This is due to the velocity envelope of the projectile design not being reached. Each projectile design has a velocity range in which it is intended to perform. Projectile designers develop their defensive hollow points to perform in this range and to meet certain criteria. If the projectile’s impact velocity is higher/lower than these parameters, the projectile will fail to perform. Not only does this include the projectile over expanding and fragmenting from excessively high velocity, but also providing no or unreliable expansion when dropping below the velocity threshold in which a projectile is designed to perform.
This failure from lack of velocity isn't typically seen in bare gel shots as most JHP designs will typically expand in this medium. However, it becomes all too evident when the FBI heavy clothing barriers are added in front of the gel block. Often times, the projectile will become clogged with clothing and lack the residual velocity to push the hollow point cavity open through fluidic contact and the clothing "plug". In successful heavy clothing tests, often times fibers of clothing are blown into the wound tract, sometimes in excess of 6 to 8 inches (depending on the velocity and the severity of the wound) and with duty caliber handguns, a good average is 5 to 6 inches.
What the projectile is doing is utilizing its velocity to push fluidic tissues into its hollow cavity, which results in expansion and an increase in frontal area of the projectile. This is often times referred to as "mushrooming" by some or simply expansion by others. Because the projectile is spinning in a circular motion, the denim is dispensed throughout the wound tract during expansion. This is typically seen upon initial opening and ends when the projectile is fully expanded, although there are instances where the plug of heavy clothing can be carried to the resting place. This is typically seen with lower velocity handgun cartridges and bonded hollow points in my experience.
Heavier projectiles, such as Remington's 102-grain Golden Saber offering is a prime example of this. When fired from a Walther PPK/s, chronographed velocities only reach an average of 901 feet per second. This is a 4.14% decrease in velocity over the 940 feet per second advertised velocity from Remington. Velocities from the sub 3-inch barrel of handguns such as the M&P Bodyguard are even lower. During my testing this load failed to expand from both handguns resulting in penetration in excess of the FBI 18-inch maximum.
A less "traditional" approach (and one which should be mentioned) is ramping the velocity higher than average, while utilizing a standard or heavier weight projectile. Companies such as Buffalo Bore, Underwood and Double Tap are famous for producing performance ammunition, along with the age old classic company; Cor-Bon. While this approach can lead to consistent expansion and the desired penetration, they do come at a price. Namely the higher pressure loads directly result in harsher felt recoil and a more noticeable muzzle flash signature. The heavier recoil leads to slower split times between shots. One example of this is Federal’s 99-grain Tactical HST load with an advertised muzzle velocity of 1,030 fps.
I personally carry a micro .380 Auto as a deep concealment firearm and also a backup handgun as needed. This small, lightweight, easily concealed handgun offers superior capacity, recoil mitigation, a slimmer profile and is consistently easier to score quick, well-placed shots with than a J-frame .38 Special snub nose revolver of (roughly) equal size and weight. Given the limited choices in good performing hollow points, I personally take a more traditional approach in terms of ammunition choices for my micro 380. My number one choice and personal carry load is the Winchester 95-grain flat point FMJ.
While I am not normally one to advocate the carrying and usage of full metal jacket ammunition for personal protection, in this caliber FMJ provides peace of mind knowing you will get consistent penetration deep enough to reach vital organs. While the initial wound cavity might not be as drastic as a JHP, it has consistent performance from start to finish. The reason I choose a flat point over the more traditional round nose FMJ is due to the added and wider frontal area. This flat nose acts much like a 148-grain Mid-Range Hollow Base Wad Cutter from a .38 Special, producing a more pronounced wound cavity than that of a round nose, with penetration that leans less on the side of over penetration. Another advantage to the flat point is it is less likely to deflect off of bone or other tougher mediums, and will be less likely to push its way around vital organs (more likely with a round nose).
While I and some others prefer to carry FMJ ammunition for the added penetration, the best performing .380 Auto JHP load is, in my opinion, hands down the Hornady XTP 90-grain JHP. This controlled expansion JHP design is the only one I have tested that will consistently provide enough penetration to meet the FBI protocol depths. Due to this it is the .380 Auto JHP load I recommend for self-defense. With an impressive advertised velocity of 1,000 feet per second, my chronograph results came in 4.9% lower through the Walther PPK/s, averaging 951 feet per second. While expansion is considered "minimal" at .40-.44 of an inch, the disruption to tissue due to this expansion places it above FMJ in terms of terminal performance. Penetration averages 13.5 to 14.5 inches which exceeds the FBI 12-inch minimum. It is also a great choice for those who may worry about over-penetration with FMJ loads.
So, back to our original question, is the .380 Auto obsolete? Overall, the .380 Auto can be considered a "dated" cartridge, especially by those who have jumped on the 21st century "micro 9" band wagon. Let’s face it; a 9mm SIG Sauer P365 does bring a lot to the table. However, the .380 Auto does bring several noteworthy advantages to the table over the micro 9s. The most obvious of these is simply being chambered in a much smaller and lighter package.
Modern .380 Autos can actually be smaller and lighter than many traditional .32 Autos. This reduction in size has led many to wonder if there is even a need for the .32 Auto today. So, a .380 Auto can be noticeably smaller in size and lighter in weight than a 9mm Parabellum. This in and of itself is reason enough for it to remain viable for personal protection. In addition though the .380 Auto also has less felt recoil and better recoil mitigation leading to faster follow-up shots compared to the micro 9s. Your average .380 Auto is narrower, holds more cartridges and is faster to reload than a J-frame .38 Special. Compared to a .25 and .32 Auto the .380 Auto puts a larger diameter and heavier payload on target. So, no, I do not think the .380 Auto should be put out to pasture. It remains a viable option for those men and women looking for a very light, compact and easy to conceal handgun for personal protection. I expect the .380 Auto to be with us for many years to come.
If you have any thoughts or comments on this article, we’d love to hear them. Email us at FirearmsNews@Outdoorsg.com
About the Author:
Michelle Hamilton has a Bachelor’s degree in Criminal Justice/Homeland Security, is a serious student of wound ballistics, military history, small arms design and manufacturing and is a competitive shooter.