Mouse sensitivity

Hi! I got the game from EGS, and I'm loving it. Question about sensitivity in game. When I'm using turret, or being in walker, using sentry on heavy class, the mouse aiming is super slow. Is this suppose to be like this? When I checked some youtube videos about the game, ppl are aiming much faster and doesn't look as slow as mine. When I'm playing as soldier and using guns it's working fine.