I've shot damascus barreled SxS's for ten years - have tried to keep my loads under 7000psi. IMHO it doesn't matter what powder is used - 7000psi is 7000psi be it BP or any nitro. My BP load is 70grs of 3F and 1oz of shot - fiber wads. If my gun hasn't blown up in a 130 years, it isn't gonna now with 6 or 7000psi loads. Any American made double of years past was built plenty stout [ not like those skinny British guns ] and should be safe with any pressure curve if it's under 7000psi. Paul