
If possible, launch them so they take falling damage too. Destory their cover, or use the AoE to dislodge them. Once enemies hide, use explosiive rounds and rail type upgrades to make your sniper rifle into a cannon. Also, don't forget to zoom in the scope at such extreme ranges, some enemies are very hard to see. At all times, try to ensure only one enemy at a time has any LOS, prefearbly ineffective though. You may see a red glow through the rolling terrain, a truncated red beam, or nothing at all in some cases. You won't always see the red beam, so be careful: Spot enemies first, assassinate, then scoot to safety. Looking downward will change camera angle for spotting and enemies won't have LOS. Get in position behind event horizon, so you can aim at head, then drop so terrain intercepts shots. Shoot and scoot, don't let a single incoming round make contact. Use the roll of terrain, since just like you, enemy scopes may bypass. Then hopefully surprise and take them out. Next, creep forward until enemy can be sighted without them having a shot, preferably without being alert. So, park allies and keep forcing them to stay out of LOS.

Ally snipers won't fire unless attacked within a limited range :/. Enemy snipers can outrange the player's (player max is roughly 375 meters).

Use the roll of terrain (or terrain objects) to sneak within range. I know, I sound crazy, but it is the best defense.
