@Lince Store the shooter object rotation to a variable, and when instantiating whatever you are to shoot, set its rotation to the shooter's, which is the one you would store. And then, use the Set Velocity action, giving the value to the Z axis. Possitive. Negative would mean 'backward'
Although I agree with @gregmax17. There should be the option to reference to Unity basic vectors, and a multiplier to change that vector.