Let's see, Remington SxSs - 1873, 1875, 1882, 1889, and a A, B, C, and three F grade 1894s. Also a Model 10, 11, 31, and a 870. I shoot all the guns as often as possible seeing how I run the shotgun venue at the local club three times a week. All the SxSs are Damascus barreled except the three F grade trap guns. All Remington shotguns were nitro proofed. Remington was the one who made barrels without a weld running down it's length, making it about the strongest barrel at that time, be it rifle or shotgun. They'd start with a 9" long 2" round hunk of steel with a 1/2" hole drilled in the middle. This they'd heat and put in a rolling mill and roll it out to what ever length they wanted. They made rifle barrels for all over the world because no one had to worry about a weld letting go. Not sure of what pressures the shotguns were proofed at, but I'd have to think that over the years just about everything at some time was shot through them. I reload and keep pressure to around 8000psi or less. I worry more about cracking 100+ year old stocks than blowing a barrel . Clang, does your C grade have the etoile pattern ? In Semmers book he claimed it was the only pattern he ever saw on them. My does. I had Brad Bachelder redo the entire gun. Sadly, he just passed away.