....With this degree of variance in barrel strengths we must rely on barrel proof test marks an actual barrel dimension if accidents are to be avoided.
Thanks for following up Doug and Jim, I was thinking there probably is a bit more to it than just relying on proof marks and the measurements that would have gone along with it.
Craig:
IMO for whatever it's worth there certainly is. Those two eyes you have can provide very valuable information to your brain about the apparent condition of barrels and A close examination should automatically be made of any older shotgun. Otherwise short of magnafluxing I know of no other way to really tell the internal condition of barrels.
Time itself isn't kind to objects made from steel and iron and they both want to return to their original state. I wouldn't disregard that letter poster earlier put out by Ithaca entirely as an attempt to convince users to buy new shotguns. From what I was told by metallurgists back when I was in the metals industry there's truth to it.