Define better.
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.
.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. However, the cases are a different size. .380 is also known as .380 auto, 9mm Kurtz, 9mm Corto, 9mm short or 9x17. 9mm typically refers to 9x19mm also known as 9mm Parabellum or 9mm Luger. You cannot fire a 9mm Parabellum cartridge from a .380 handgun. The 9mm cartridge will not fit into the chamber of the gun. However, if you were to pull the bullet out of the .380 case and put it into a 9mm Para case the resulting cartridge will work just fine.
It depends on a couple of factors, but in general, a 9mm is louder because it's a higher pressure cartridge than the .380.
No, the bullet will not seat.
2mm in case length.
No, the calibers and chamberings are completely different. It is not safe to attempt to fire any caliber of ammunition in a gun, other than what is stated on the barrel. actually the 380 caliber is almost equal to the 9mm. the 380 caliber is often refered to as a 9mm short. the difference is the 9mm case is slightly bigger then the 380 case and the 380 bullet might be a little lighter.......................
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.
380 and 9mm ammunition IS NOT INTERCHANGEABLE.
I'm assuming you're asking if a .380 round can be fired in a 9mm handgun. The answer is, yes, it may be possible, but it is not a good idea to fire any cartridge in a gun other than the correct caliber for that specific gun.