if you ever get the chance to visit a pressure lab, it's well worth it. I've visited at least half a dozen now, some more than once.
It can go far beyond what I just described. The most thorough lab I've visited (they do a lot of work for other companies) is a good example. I spent most of day with one of the techs while he ran a test on ONE combination of bullet and powder. Of course, my questions and photography slowed him down some, but even without my "delaying tactics" it would have taken at least three hours for him to simply prepare two dozen test loads.
Among other things, when doing piezo-electronic testing the brass itself has to be tested for hardness, since piezo testing is done through the pressure on the side of the case. This was done with an expensive hydraulic machine, filling the case with fluid and measuring how much X amount of pressure expands the case walls. And of course that requires an average of several cases.
Unfortunately, not many pressure labs give tours, generally because they're too busy.
