To Jack’s point from the Squad Leaders instructions part of Fm7-10 (from 1942 I believe)
Unless otherwise ordered by the platoon leader, the squad leader permits his squad to open fire only when fire action is necessary to cover a further advance. At the first firing position, the squad seeks to gain fire superiority over the enemy to its front. Fire superiority is gained by subjecting the enemy to fire of such accuracy and intensity that his fire becomes so inaccurate or so reduced in volume as to be ineffective; once gained, it must be maintained. Unless supporting weapons or other units are able to maintain fire superiority without any help from the squad, enough members of the squad must remain in position and continue the fire to maintain it.
The automatic rifle’s capacity for putting down a large volume of fire makes it especially useful for this purpose. Meanwhile, other members of the squad move forward, take up firing positions closer to the enemy, and, by their fire, cover the forward movement of the rearward members. By this combination of fire and movement, the squad advances close enough to capture the hostile position by assault.
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