The 20-mm gun on a self-propelled mount combines the fire power and mobility of an antiaircraft gun with the accuracy and penetration of an antitank gun. It is insufficiently armored, however, and this fault must be offset by making good use of cover and by fire control.
The smallest unit in battle is the section of two guns. Use of single guns, except for individual tasks like the engagement of enemy observation posts, is exceptional. Ground observation is most important; every spare man must be employed on it, and must be made personally ambitious to spot targets.
During assembly, antiaircraft-antitank troops usually take over protection against air and land attack. Guns must be sited so that attacking aircraft can be engaged from reverse slopes, while, moving the gun to a position on the forward slope, it is possible to bring under fire the enemy approaching on the ground.
The antiaircraft-antitank troops support the advance of the infantry and other arms. For this purpose the antiaircraft-antitank guns should be sited to a flank, to exploit their range fully without endangering the advancing German troops. The addition of 100 yards, more or less, to a flank hardly interferes with the effectiveness of the 20-mm gun, whereas it does affect the enemy's infantry weapons by widening the target.
The platoon or section commander and his runners follow directly in the rear of the attacking infantry or the assaulting engineer detachment. The commander reconnoiters good positions and good targets for the guns.