Gun Shield is a Defensive Ability utilised by the Legion and Legion Prime Titans. When activated, a Particle Wall is deployed, surrounding the barrels of Legion's Predator Cannon. This shield will remain activate for a short amount of time, and stops legion from sprinting, meleeing, and getting Terminations. He can still employ Electric Smoke, Mode Switch, Power Shot and shoot regularly, however.
However, the titan cannot deactivate it and you cannot stop the predator cannon while its on, so you can get trapped in thermite from the Scorch
and Nuke Ejections.