Case length.
Glock is a brand. 9mm is a caliber size. So, there is no difference between a 9mm glock and a 9mm of another brand as far as caliber size.
No such ammuntion as 9mm rugger
9mm = .355 40 cal = .40
I personally don't make 380 handguns, never have, BUT, the 380ACP round was very popular in the early to mid 20th Century, especially in South America and Europe, where citizens were limited to handguns of .380ACP (or 9mm short), or smaller. There has been a resurgence of the .380ACP's popularity in the early 2000's. Although it is not as powerful as a 9mm Parabellum, it is still adequate for personal protection. These weapons can be made very small and lightweight, which appeal to some owners. Due to this popularity, almost all gun manufacturers have designed modern pistols that fire the .380ACP.
Same round, different weapon design.
Different makers. The cartridge used is the 9x19.
Although the two bullets have the same diameter, one cannot shoot a 9mm Parabellum round from a .380ACP pistol. The .380acp is called a 9mm short in other countries. Its case is 2mm shorter than the 9mm Parabellum. This means that if one chambered a 9mm in a .380, the breech would not be fully seated. Often, modern handguns would not allow the trigger to actuate the hammer due to a disconnector. If one were able to get a hammer to fall, the design of the .380acp pistol is meant for the chamber pressures that .380 ammo produce, the 9mm produces much more pressure. The result would likely be a severe malfunction, maybe even a explosion with bits of gun flying off like shrapnel. The shooter would like be injured, how severely would depend on how the gun parts fragmented.
There is no difference- Luger is a name that is commonly used in America and Parabelum is used in Europe, they are both 9x19.
The 9mm Parabellum is longer than the .380 ACP (also called the 9mm Short) They do not interchange.
9MM Luger can be Ball ammunition. Ball just means it is a jacketed round nose bellet.
9mm (usually called 9mm Luger or 9mm Parabellum) almost always has a higher muzzle velocity than the 380 ACP (also called the 9mm short, 9mm Kurtz, and 9mm Corto). The two bullets are essentially the same diameter however the 9mm Parabellum is almost always a heavier bullet than the 380 ACP with a larger powder charge and a significantly higher chamber pressure.
9mm will have the least kick, follwed by the 40, then the 357.