lots to look at and smoke in to be sure you have correct geometry and bearing surfaces. You have three principle points of contact on a Purdey double under bite system, the hinge pin/hook, the breech face/standing breech and the rear bite and its corresponding slot in the barrel lump. The forward bite should have little bearing if any as its principle purpose is to keep the top lever to the right when the gun is open. A strong top lever spring should seat the bolt firmly on its own. Check all points of contact and for no excessive bearing on your forward bite and you should have a very good idea of what is stopping your bolt travel. Hope that helps.
Steve
