The Marines in the photos are with the 11th Marine Expeditionary Unit, which deployed in March to support operations in the Middle East.
Source: Marines on way to Middle East seen using rifles with anti-drone smart scope
tl;dr: sight detects best time to shoot a drone down, only allows boom when so. imho, fine mesh nets in shotgun or 20mm or maybe 30mm rifle grenade shell. or even hand tossed, 2 or 3 second delay after tossing at drone.
