Use of the field-glass (laser index of the purpose, range finder) limits the movement. Using the field-glass I cannot step through a fence. When it in hands I can stand, an inclination to the left and to the right, to lie or run. All other actions and provisions of a body, turn through a shoulder in left and to the right are not available.
When I run the field-glass I hold in the left hand. The right hand is free and does not use the gun. The field-glass and the gun should be used together necessarily, in situation without lying. I stand, I sit or in the movement the field-glass in left, the gun in the right. Not easy to make firing from the gun from one hand. But in a close combat, at a small distance can make success.
Normally, when two hands are occupied in any situation when I use field-glass, I change range of the overview. In an operational situation, standing or sitting, it is enough to take in the left hand to lower the field-glass the right hand with the weapon down.