dont change the basic side view of the curve of the as it is now, unless you are familiar with doing so (to make it easier or harder to engage) but you can contour the edge that the plunger rides on, so that it wants to snug the face inwards, towards the frame. -so tht it contacts more of the outside of the edge. also, DO check the plunger tube to see if its loose. thats a common symptom.