- The sealing of the combustion chamber between the pipe wall and the floor.
- Thanks to the pulls in the barrel, it gives the bullet a rotation around its longitudinal axis ( twist ).
- Serves as the rear guide of the bullet in the barrel.
The guide bands are usually made of copper, a softer metal as a tube and floor, so that they in the coatings can be pressed in. Rarely, as for example in the German Paris Gun , steel used. Depending on the load, one or two guide straps are attached. The guide bands around the bullet always have a slightly larger diameter than the inner diameter of the barrel in order to achieve a complete seal when firing. At the same time, when accelerating, the bullet receives a rotational movement around the longitudinal axis, i.e. the twist, which affects the precision of the flight path . Especially in the case of heavy artillery shells, the guide bands can be designed as twist guide rings. During the manufacture of the bullet, longitudinal grooves into which the cables can engage are worked into the twist guide rings. This enables a form fit between the projectile and the rifles when the projectile is placed in the barrel, which increases the service life of the gun barrel. If grenades are not set correctly, ie the connection of the grenade to the barrel with guide straps does not result in a clear click, the pipe may burst or crash .
The guide band is rarely found in ammunition for small arms. The bullets are mostly deformed over their entire surface, i.e. pressed into the runner profile in such a way that the outside of the bullet or, in the case of jacketed floors, the bullet jacket adapts to the runner profile.
The grooves in the sub-caliber Minié bullets for muzzle-loaders fulfilled a double task . When the shot was released, the hot gases penetrated the hollow floor and expanded the projectile. The bullet grease required for lubrication was located in the grooves, while at the same time the elevations provided a seal against the barrel.
With modern ammunition for handguns, the function of the guide band is mostly fulfilled by ductile projectile or projectile casing materials, but there are also special designs with dedicated guide bands. In the hunting sector, so-called copper hunting bullets with up to five guide bands are used, whereby the guide bands are not attached but are made from solid material when the projectile is manufactured.
- Walter Stutz: Shooting apprenticeship. Birkhäuser, Basel 1959.
- R. Böhm: The German Guns 1939-1945. Edited by FM von Senger and Etterlin . Bechtermünz, Augsburg 2002, ISBN 3-8289-0524-2 .
- Norbert Klups, Lead Free Bullets, Volume 4 / KJG, DJZ, October 2005 edition, (accessed on December 21, 2009) ( Memento from March 4, 2016 in the Internet Archive ) (PDF; 134 kB)