During the loading of tubular weapons, the shell is manually or mechanically brought into a position upstream of the weapon breech plate, where it rests on a loading tray and its axis is aligned with the barrel bore axis. From this position the shell is accelerated and rammed by the rammer into the tube. Thus, the rammer drive must give the shell a high acceleration over a comparatively short distance, which requires a correspondingly high driving forces and a short-term release thereof.
Spring means, e.g. motor-pretensioned helical springs have proved satisfactory for driving the rammer (EP-A-256 250). In the pretensioned position the spring tension is absorbed by a release mechanism holding back the rammer.