Left Trigger

From Gears of War Realm - Gears of War Wiki Strategy Guide

The Left Trigger allows for over-the-shoulder aiming with a reticle, as opposed to blind firing. Additionally, when used with a grenade, the left trigger shows the projected path. When used behind cover, the left trigger causes the character to lean out and aim. Shooting is considerably easier because of the reticle, and also more accurate than blind fire. With certain weapons, such as the Sniper, the Right Stick can be depressed to allow for zoom when the left trigger is pulled.