. "Damascus barrels were never proved WITH Nitro powder." Like peak psi with BP somehow is different than peak psi with Nitro?!?
The catch here is "Peak". I do recall reading that in the early days, in England at least, that nitro proof was done with black powder. the reason cited was that in those days they did not truly have a suitable smokeless to proof the gun for both black & smokeless at the same time. A coarse black could be loaded as to give the needed max/peak chamber pressure while simultaneously giving a suitable load to test the entire barrel. The fast burning smokeless powders of the day when loaded up gave an increase in chamber pressure but with a quick falling of that did not test the forward 3/4ths as heavy as did the black used. A still heavier load of smokeless could actually damage the chamber area but never truly "Proof" the forward portions.
The French of course did proof "With" smokeless but even with their tremendous pressures developed it is questionable if they actually gave any stronger overall proof than did the Brits & were likely skating on thin ice in the chamber area.
