The space requirement behind a breech-loading, for example, large-caliber cannon, also known as a breechloader, is determined, on the one hand by the recoil distance and, on the other hand, by the length of the projectile and propellant charge. The length of the projectile and propellant charge is the decisive factor, for example, in the case of fin-stabilized guided projectiles or in the case of fire out-of-battery systems. In the case of fin-stabilized guided projectiles, advantageous projectile lengths are those which are well above a necessary recoil distance. In the case of fire out-of-battery recoil systems, the ammunition is loaded with the weapon in the recoiled position.
If the projectile and propellant charge are significantly longer than the recoil distance, then the weapon generally moves into an index position for loading the ammunition, or the space that is necessary for loading the ammunition is made available over the entire aiming range in the weapons carrier. The space for loading the ammunition results in a high weight and volume of the weapons carrier, while moving into an index position reduces the rate of fire.
A loading system for conveying ammunition from a magazine chamber located behind the weapon is described in DE 199 32 562 B4. This loading system comprises a bridge that bridges the space between the magazine chamber and the weapon in its loaded position. The loading bridge itself consists of two complementary halves. The first half is pivoted on the nonrecoiling part of the weapon in such a way that it rotates about an axis of rotation that is perpendicular to the bore axis of the weapon, and the second half is pivoted on the wall of the magazine chamber in such a way that it likewise rotates about an axis of rotation perpendicular to the bore axis of the weapon. The goal here is to bridge the space needed or left free for the recoil of the weapon by a pivoting loading bridge.
Various breech mechanisms are disclosed by DE 103 17 177 A1, DE 197 29 293 B4, DE 198 23 785 C2, DE 199 41 066 B4, and DE 199 28 277 C2.
DE 103 17 177 A1, for example, discloses a sliding block breech mechanism, which, to allow it to be guided without the use of an external drive, is guided along a curved track of a guiding device that is fixed relative to the cradle and maintains itself in the opened position.
The transverse action breech mechanism described in DE 198 23 785 C2 is distinguished by the fact that when the opener lever is swiveled from its initial position to its final position, the sliding breechblock is displaced from its closed position to its opened position.
Other well-known breech mechanisms are cylinder breech mechanisms, roller breech mechanisms, trapdoor breech mechanisms, etc., as well as screw-type breech mechanisms.