The skirmishers' role was to precede the main body in 'open order', forming a protective screen and firing at the enemy in a way designed to gall and disrupt - and also to form a defensive screen to counter the enemy's skirmishers. This inevitably led to the selection of men who were superior marksmen, to be armed with rifled weapons (shorter than a musket and sometimes referred to as 'carbines') and charged specifically with the task of killing or disabling enemy officers or NCOs - thus undermining the cohesion and steadiness of the enemy ranks. The numbers may seem few, and in practice the Prussians found they had insufficient numbers (even though the Fusilier Schützen had been increased from 10 to 22 in 1798), but even when used in large numbers the methodology was to have only a small proportion of them rotated so that they would not run out of ammunition, and so they could always fall back on the main body when threatened by cavalry.