Thanks for the response, Chuck. My college is getting more deeply into the NDE/NDI world and I'm always trying to think of applications. But I suspect that shotgun barrels (especially Damanscus) are as much art as science, and NDE would only work to give you a "no go" if obvious cracking was discovered. I know gunsmiths have used simple tests like liquid penetrants to check recievers,slides, etc. for cracking--do you know of other applications that are used in the gunsmith shops?