Firers and assistants should learn to judge ranges by frequent practice under varying conditions. The firers should be trained to approach as close as practicable to the target and to fire if possible at point-blank range for the greatest results.
a. Point-blank range.
(1) Effects. At very close (point-blank) range almost all of the burning fuel can be fired at great velocity directly through ports and openings into the target. Maximum casualties and damage are caused in the hostile position.
(2) Protection. Common sense precautions are taken to prevent casualties to friendly personnel from possible ricochet or rebounding of flame. If the target includes a vertical wall at a right angle to the firer or other friendly personnel, the weapon should not be fired at closer than 7 to 10 yards. When the weapon is fired at small openings in a bunker or pillbox, the firer and other members of the assault squad should not approach closer than 7 to 10 yards from the target.
b. Other effective ranges.
(1) Open fields of fire. When thickened gasoline is used, portable flame throwers may fire with considerable effect as far as 40 yards under normal conditions, depending on wind direction and wind speed. Under the same conditions, liquid fuel maybe effective at 20 yards. Results and accuracy are not as great as at point-blank range.
(2) Jungle or thick underbrush. If the target is located in jungle or thick underbrush without cleared fields of fire, the effective range of the flame thrower is reduced by as much as one half, depending on the nature and density of the vegetation.
c. Ineffective ranges. Although the flame may reach considerably farther than the ranges stated in b (1) above it may be useless because of the steep angle of descent and because much of the fuel is burned before it reaches the target.
23. WIND DEFLECTION.
Wind is an important factor because of the low velocity of the flaming fuel. Wind can lengthen, shorten, or deflect the flame.