what's the difference between 380 acp and 380 auto
.380 ACP The .380 ACP (9×17mm) (Automatic Colt Pistol) is a rimless, straight-walled pistol cartridge developed by firearms designer John Moses Browning. The cartridge headspaces on the mouth of the case.[2] It was introduced in 1908 by Colt, for use in its new Colt Model 1908 pocket hammerless semi-automatic, and has been a popular self-defense cartridge ever since, seeing wide use in numerous handguns (typically smaller weapons). Other names for .380 ACP include .380 Auto, 9mm Browning, 9mm Corto, 9mm Kurz, 9mm Short, 9×17mm and 9 mm Browning Court (which is the C.I.P. designation). It should not to be confused with .38 ACP, from which it was developed.[3]
Rifle Formerly, rifles only fired a single projectile with each squeeze of the trigger. Modern rifles are capable of firing more than one round per trigger squeeze; some fire in a fully automatic mode and others are limited to fixed bursts of two, three, or more rounds per squeeze. Thus, modern automatic rifles overlap to some extent in design and function with machine guns. In fact, many light machine guns (such as the Russian RPK) are adaptations of existing automatic rifle designs. A military's light machine guns are typically chambered for the same caliber ammunition as its service rifles. Generally, the difference between an automatic rifle and a machine gun comes down to weight, cooling system, and ammunition feed system. Rifles, with their relatively lighter components (which overheat quickly) and smaller capacity magazines, are incapable of sustained automatic fire in the way that machine guns are; they trade this capability in favor of increased mobility. Modern military rifles are fed by magazines, while machine guns are generally belt-fed. Many machine guns allow the operator to quickly exchange barrels in order to prevent overheating, whereas rifles generally do not. Most machine guns fire from an open bolt in order to reduce the danger of "cook-off", while almost all rifles fire from a closed bolt for accuracy. Machine guns are often crewed by more than one soldier; the rifle is an individual weapon.