Oh my- This is a wrinkle. Does the action lock up tight? How's the headspace? Back to the firing pins; Numrich (gunpartscorp.com) sometimes has firing pins for the '78. If your planning on replacing them I would look there first. But, if the action is loose and/or the headspace is way off then replacing the pins becomes secondary. Are you hoping to shoot this gun?

Hank

Yes, I did write a book. It's called "The Classic English Double Barrel"