Question about the 380 Cartridge
Question: Can a firearm chambered in the .380 cartridge shoot a 9×18 cartridge?
Answer: The simple answer is no. That doesn’t mean there aren’t exceptions.
Safe exceptions? No, there are no safe exceptions.
Is a gun chambered for the 380 cartridge capable of firing the 9×18?
But…I find it completely plausible that a 9×17 (.380 cartridge) COULD be capable of firing a 9×18. The original question was asked using the Makarov clone IJ-70 380. Such a gun often times suffers from less perfect tolerances and less than amazing quality control (many guns do, especially “mil-spec” clones). It’s conceivable that someone could shoot the cartridge (9×18) out of the gun chambered for the 380 cartridge. The .380 cartridge is a 9×17 but is also known as the “9mm Kurz”; “9 milli-meter Browning short”; “9mm Corto”, amongst other names.
Damage could be sustained by the firearm AND/OR the shooter if the 9x18mm were to be shot out of the 380 (cartridge) chamber. The length of the (9x18mm) round is such that it could potentially bring a gun chambered for the 380 cartridge into full battery allowing it to be fired; potentially it could even repeat the chambering and fire multiple rounds-though unlikely. The main concern is that the head-spacing of the chamber in comparison to the dimensions of the non 380 cartridge (9x18mm in this case) allows for excess pressure to be created in the chamber and the throat areas. Such an increase in pressure could erode the chamber, cause too much pressure on the link-up or simply blow up a portion of the slide/frame. It’s unlikely that a single shot could cause major damage, with the quality of metallurgy now available, but I have seen too many guns blow up due to shooter error or hot cartridges to say that it’s a safe practice.
DISCLAIMER: ALWAYS USE THE PROPER AMMUNITION, AND CHECK FOR HEAD-SPACING AND BARREL DAMAGE PRIOR TO FIRING ANY FIREARM. THE AMMUNITION THAT THE FIREARM IS MADE FOR (AND THE ONLY AMMUNITION YOU SHOULD BE SHOOTING IN IT-WITHOUT OBVIOUS INTERCHANGEABILITY LIKE A 357MAGNUM TO A 38 SPECIAL) WILL EB STAMPED ON THE BARREL AROUND THE CHAMBER OR ALONG THE LENGTH OF THE BARREL, AND SHOULD BE SUBSTANTIATED SOMEWHERE ELSE ON THE FIREARM AS WELL.
Certain cartridges are able to be shot out of the same chambers as other cartridges. The .380 cartridge is not one of those. Theoretically a 9mm or substantially similar cambering in a revolver could fire a shorter (same diameter cartridge/bullet) safely, but I am unaware of any extensive testing to show wear characteristics or safety concerns for such an occurrence. The reason that the revolver cylinder has so much leniency for such applications, is that the forcing cone of a revolver’s barrel is afforded less tolerance by virtue of its design compared to a semi-automatic handgun. This bigger amount of play for the seating of a bullet/projectile, allows for a shorter chamber stabilization protocol than that of a semi-automatic pistol. Often, shorter cartridges will lead to lead-shaving where hot lead is sliced off of the edge of a bullet’s circumference with certain shots. This can be uncomfortable and in the case of extreme lead shaving, dangerous.
The 380 cartridge
The 380 cartridge has become a popular chambering in the last 2 decades; due in part to the concealability of the firearms in is able to be chambered in. Additionally, many people don’t realize that the 380 cartridge has enjoyed notoriety due to the amount of gang-warfare and street shootings that it is involved in and the amount of deaths it has been responsible for from the projectile perspective.
Often, those people carrying guns with them for gang activity and nefarious purposes needed a cheaper firearm; one which was easy to hide, and wasn’t missed as much if it had to be ditched. Until very recently there was an abundance of cheap 380’s from Eastern Bloc countries and Asia; and the ammunition was usually quite inexpensive. All along, the 380 cartridge was available in a wide amount of areas, and there weren’t a lot of expensive guns chambered for the 380 cartridge (the Walther PPK and some others are exceptions). When the 380 cartridge began racking up kills on the street in urban ganglands across the United States, civilians began to pick up on its viability as a concealed carry firearm.
Sidenotes for the 380 cartridge
The 380 tends to be a relatively snappy recoiler. The muzzle flip for guns chambered for the 380 cartridge tends to be heavy, with follow up shots not as easy as for more substantially sized guns. The lightweight of the smaller firearms chambered for the 380 cartridge, combined with the substantially similar ballistics of the 9×17 round (due to similar powder loads and similar or smaller projectiles), led to this muzzle flip. There are rumors that the penetration of the round and the slower follow-up shots are inadequate for TRUE self-defense purposes, but the homicide reports and ballistic gelatin results tend to refute those rumors well.
Ballistics for the 380 cartridge
This isn’t an in-depth exploration on the ballistics of the 380 cartridge, but for the purposes of this topic, the ballistics of the 9×17 (.380ACP) are generally ranging from 180 foot lbs of energy to 255 foot lbs of energy with 850-1200 feet per second velocities. Bullet grain weights generally come in 70, 80, 90, 95 and 100 grains. The velocity tends to move in tandem with the grain weight (the lighter bullet, the higher velocity); the sweet spot for muzzle energy tends to move in tandem with the heavier bullet weights, though some specialty loads find optimum velocity and energy at polar opposite ends of the spectrum. A typical bullet weight is 90 grains with about 950-1150 fps velocity and 200-215 foot lbs of energy delivered.
Seemingly, the ballistics for the 380 cartridge makes it adequate for most close range self-defense situations-depending on whom you ask.
The 380 cartridge should not be fired out of a gun not chambered for it. Similarly, the 9×18 cartridge, the 9×19 and other similar one-off rounds should not be fired out of a gun chambered specifically built for and chambered in the 380 cartridge. While you may be ABLE to make a gun function in such a way, it can be extremely dangerous and even deadly to do so.