FO's or On Map Guns?

[Bear]

There are two factors to be considered.

1. The length of the MLR and range of the FO/battery relative to the MLR.
   
2. Battlefield situation: Has the enemy broke through, infiltrated the MLR and overrun or bypassed the FO. And the inverse situation such as a rapid advance that allows the battery LOS to use direct fire...a most desirable situation indeed, a battery in direct fire mode. Also the condition of the battery, are all tubes available and had time to set up for on call barrage.