I think a bore micrometer, wall thickness gauge and chamber gauge are very important and useful tools. I own all three and find them great for analyzing these shotguns, specifically for evaluating whether a gun is 'in proof'. I also think they give an estimation of a gun's safety, but stop short in comparison to actually proofing a gun. These
tools, or instruments are very helpful to the knowledgeable gun person. However, Most Americans who have guns, don't have a clue what a barrel wall thickness gauge or a bore micrometer is, let alone how to use one or understand the data they generate. Just my humble opinion, but I only buy guns which are in proof, if I can help it.
