Okay, so you want the bullet to change direction towards a moving player, so it wil always hit. Kinda like a heat-seaking-bullet.
Wel you have the bullet action 'set angle of motion'. That wil ask you for an angle.
The needed angle you get with an expression. Assuming that the name of the bullet = "bullet' and the name of the player = "player" it is:
Just fill that in the 'set angle of motion' action.
Basecaly you use the same tool to change angle as you use to do the motion. If you use 'rotate toward position' (by instance) you rotate the physics world, while you need to rotate things IN that physics world. You will make things go stuck by pushing them into solids, the paths will go erratic, in fact you just break the physics world.
A little warning; if the bullets always hit, the player goes erratic too.
Hope i helped.