Primer tipping or flipping is usually caused by a burr or nick in the slot of the ram where the primer arm and primer cup pass. This burr catches the primer cup and compresses the spring and when it suddenly snaps free, it causes the primer to tip or flip over.
You will find the burr at the point where the 1/4 " wide primer arm slot on the ram meets with the shell holder slot. Remove this burr with a file. It is easy to get at with the turret removed.
