Machine gun fire scares no one, help?

Hey MG player here, i have no idea what im doing wrong, im literally removing a general direction and the split second i stop firing they just peek their heads out again and try to look for me.. like what? You just got barraged by a bullet rain and you think its a good idea to stick to that same exact spot and try again? It doesn't feel like i am pressuring the enemy team, only holding them off for a short time. feels like the MG is usseles and it doesn't really scare anyone away from their position or supress them. Fired an entire mag from an angle at a window, the guy just thought nope and kept staying there firing his gun. Like what??? Shouldn't you be relocating? What am i doing wrong? I have about 1000 hours into the game and its embarrasing i can't even do this role correctly no matter what i try