The only type of firearm that I'm aware of which could safely fire both would be one that does not headspace off of the case mouth (the intended method for both cartridges). This would likely be a revolver with a special clip (sometimes called a moon clip), which holds the cartridge by the groove in it's head. Don't try such a thing with any autoloader. Even when it works, it causes extreme wear on the extractor, as well as variations in accuracy/velocity, and not not be powerful enough to cycle. This information also applies to .40S&W/10mm.
A pistol chambered for .380 ACP (also known as 9x17) can fire that cartridge and only that cartridge. You cannot shoot 9mm Parabellum (9x19) or any other 9mm cartridge in it.
No it is dangerous to attempt a 9mm is a bigger bullet. More specifically, 9mm Luger is a longer cartridge that .380 ACP.
No, the bullet will not seat.
.380 ACP is 9x17mm. That's the only cartridge that gun can fire. 9x19mm (a.k.a., 9mm Parabellum or 9mm Luger) and 9x18mm (a.k.a., 9mm Makarov) are NOT compatible with these guns.
.380 ACP is 9x17mm. That's the only cartridge that gun can fire. 9x19mm (a.k.a., 9mm Parabellum or 9mm Luger) and 9x18mm (a.k.a., 9mm Makarov) are NOT compatible with these guns.
9mm and 380 both use bullets with a diameter of .355. But the answer to the question you're probably asking is, no, you cannot fire a 9mm parabellum cartridge from a .380 handgun. The 9mm cartridge is different than the .380 cartridge. Even though both are 9mm in diameter, the overall cartridge lengths are different.
NEVER SHOOT AMMUNITION IN A WEAPON NOT CHAMBERED FOR IT!!!!! Do not attempt this.
9mm and .380 bullets are the same diameter. In fact, .380 is also called 9mm Kurz(short) or 9x17. However, the caliber commonly called 9mm is 9x19, which means the cases are different size. A .380 cartridge will fall down into the chamber and the firing pin will not reach the primer. So, a .380 bullet can be fired from a 9mm gun if it were loaded into a 9mm case. A .380 cartridge would fail to fire in a 9mm gun.
No.
No! Both of those cartridges are ACP where it uses the mouth of the case to establish proper head spacing and to prevent the round from dropping too far in to the barrel. The cases are of different lengths. 9mm is 19mm (.754in) and the 380 is .680 in. The 380 will drop in to a 9mm barrel, but would be dangerous to shoot. The action of a 380 will not close on a 9mm.
No. The 9x19 (which is 9mm Luger/ 9mm Parabellum) is too long and FAR too powerful. Very unsafe. .380 is also known as the 9x17.
The 380 and 9mm are two different cartridges, and you should never try to fire anything out of any gun other than what it is designed to shoot.