Tracer ammunition, or Tracers, are bullets or cannon-caliber projectiles that are built with a small pyrotechnic charge in their base. When fired, the pyrotechnic composition is ignited by the burning powder and burns very brightly, making the projectile trajectory visible to the naked eye during daylight, and very bright during nighttime firing. This allows the shooter to visually trace the trajectory of the projectile and thus make necessary ballistic corrections, without having to confirm projectile impacts and without even using the sights of the weapon. Tracer fire can also be used as a marking tool to signal other shooters to concentrate their fire on a particular target during battle.
Tracer ammunition fired by United States military captured in a long-exposure photograph of a Japanese attack on Peleliu, 1944
Tracer fire on Finnish-Soviet border during the Winter War (1939–1940)
M2HB Browning machine gun and armor-piercing incendiary (M8) ammunition loaded. Note every fifth round is a red-and-silver-tipped armor-piercing incendiary tracer round (M20).
7.62×51mm NATO Orange-tipped FMJ tracer ammunition in a five-round stripper clip
A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constructions, including specialized functions such as hunting, target shooting, training, and combat. Bullets are often tapered, making them more aerodynamic. Bullet size is expressed by weight and diameter in both imperial and metric measurement systems. Bullets do not normally contain explosives but strike or damage the intended target by transferring kinetic energy upon impact and penetration.
7.5×55mm Swiss full metal jacket, armor piercing, and tracer, spitzer projectiles. The three bullets on the right show cannelure evolution
Round shot from the 16th century Mary Rose English warship, showing both stone and iron ball shot
Matchlock musket balls, alleged to have been discovered on the battlefield of Naseby (1645)
Minié ball ammunition