A U.S. Marine manning an
equipped with a gun shield">M240 machine gun equipped with a gun shield
A gun shield is a flat (or sometimes
curved
In mathematics, a curve (also called a curved line in older texts) is an object similar to a line, but that does not have to be straight.
Intuitively, a curve may be thought of as the trace left by a moving point. This is the definition that a ...
) piece of armor designed to be mounted on a
crew-served weapon such as a
machine gun
A machine gun is a fully automatic, rifled autoloading firearm designed for sustained direct fire with rifle cartridges. Other automatic firearms such as automatic shotguns and automatic rifles (including assault rifles and battle rifles) a ...
,
automatic grenade launcher, or
artillery
Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during siege ...
piece.
Military

Some mounted machine guns and artillery pieces are equipped with metal armor plates to protect the gunners from
small arms
A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions).
The first firearms originated in 10th-century China, when bamboo tubes c ...
fire and
shrapnel from explosions. They were fitted to some
armored fighting vehicle
An armoured fighting vehicle (AFV) is an armed combat vehicle protected by armour, generally combining operational mobility with offensive and defensive capabilities. AFVs can be wheeled or tracked. Examples of AFVs are tanks, armoured cars, ...
s and
patrol boats during the