On Paul Jones moulds I only bang on the hinge pin of the handles. However after more than 30,000 bullets cast on one of Paul's moulds the pins moved and the bullets started to be oval in shape. So banging on the hinge pins will not alleviate eventual movement of the pins (or wear), although it will take a very long time for it to occur.

When the pins no longer align properly; is it the movement of the pins, or is it wear on the mouth where the pin engages?

The pins are too tight to move precisely yourself so I do not know how Paul realigned them.

With the R&J handles and Boomer mould I do not think I will have this problem. Check back with me after I cast another 30,000 bullets and I will recheck the alignment of my mould.

Maybe moulds do have a life span and are not useable forever.

Yes John and Dave you are both correct. The pins might not be moving very much, if at all but the holes are getting opened up.This gives the pins enough clearance that they now just "slip" in to the holes. I believe that on a brand new mould the inside champher and the radius around the top of the pins is the alinement secret. As the mould wears from constant opening and closing the holes expand and the true alinement is lost. As an experiment try to fit the two bottom pins of the male half of the mould into the other side of the female mould. (the outside of the mould) This side of the holes have no ware. You will notice that the pins really are bigger than the holes. And it is only the radius on the pins that determine how much the mould can close and with precision alinement. As the holes wear enough to allow the pins to enter past the radius the cylindrical part of the pins (maybe moving a little from banging) are going into the holes when they shouldn't be. With all 3 holes 
warn like this the mould has movement and I don't know if it can be fixed. I think what Paul did, and only in cases that weren't that bad. Was to back the pins out enough so that the radius again becomes the bearing surface. This setting has to be just right. Still even with this condition the mould works well. I don't have any point in all this I guess I just find it interesting. Cast iron and harden steel pins? I can't imagine what happens to one made of aluminum.

Bob H.