Might also mention that have had extensive conversations about copper-crusher testing with pressure labs, because even as major labs have converted to piezo, they have plenty of copper-crusher barrels on hand. which some still use for cartridges that aren't all that popular, because it doesn't make sense to build/buy a piezo barrel. The main comment from the head guy at one lab was that copper-crusher barrels provide good overall pressure data (though not as precise from shot-to-shot, pressure-curve) as piezo barrels.
But the biggie is takes a lot more time to do the prep and post-work work for a CUP test. It takes far longer than most shooters would imagine just for a valid for a piezo test, including far more expensive equipment, but not nearly as much time as with CUP equipment, mostly because of all the measurements involved.
Yes, Hatcher did use copper-crusher equipment, which was state-of-the-art in his day. But it was perfectly capable of providing results to come up with conclusions about pressure and primer appearance.
