If you're with a team, try coordinating to make it choose a specific target. Otherwise, circle around it enough times and shoot it in the head.

Make sure these guys are dead first.

DO NOT run out and try to take them out in the open. Find them behind cover and aim carefully.

Listen for the electrical humming noise and remember where it is. Shoot it when you see it.

Use armor piercing weapons. Or fire. Or explosives. Or teamwork. The standard "circle around" method doesn't work nearly as well due to there being multiple Winters shields, but it's still fairly functional.

Shoot it in the laser.

Shoot them in the face.