An automatic firearm is a firearm that will continue to load and fire rounds of ammunition as long as the trigger (or equivalent) is activated or until it runs out of ammunition.
The .50 caliber (12.7 mm) M2 machine gun, the 7.62 mm NATOM60 machine gun and the M134 minigun are examples of fully-automatic weapons, as are the autocannon mounted on any number of military aircraft and used in other military applications for point defense and/or anti-aircraft defense.
So-called automatic pistols, however, are generally not fully automatic weapons, but fire a single shot every time that the trigger is pulled, automatically ejecting the spent cartridge and loading a fresh one into the chamber.
An automatic transmission is an automobile gearbox that can change gear ratios automatically as the car or truck moves, thus freeing the driver from having to shift gears manually.
In recent years, automatic transmissions have significantly improved in their ability to support high fuel efficiency but manual transmissions are still generally more efficient.
The predominant form of automatic transmission is hydraulically operated, using a fluid coupling or torque converter and a set of planetary gearsets to provide a range of torque multiplication.
It is distinguished from a fullyautomaticrifle in that it can only fire once each time the trigger is pulled.
Such perceived (but generally false, as well as highly illegal) easy conversions have attracted the attention of gun control advocates, as nominally semi-automatic rifles are much more freely available than fully-automatic ones in many jurisdictions.
For example, it is possible in the U.S. to purchase a semi-automatic M60 machine gun, but the internals are extensively modifed to the point new parts and expert machining would be needed to convert it to fullyautomaticfire.