Help please (if you can)

Im making a run and gun and when my character shoots downward, (on the ground and while jumping) he jerks up and down.

P.S. he is animated in parts

And the question is?

You probably want to know how to remove the "jerking"

without seeing your capx, this could be a lot of things..

Wrong imagepoint in the shooting animation, solid behaviour applied to your player, an event that moves the player on shoot..