I had an English Damascus 12 reproofed several years ago. It came back proofed for 12-65 (2-1/2") and 850 BAR. The told me they would prove to a higher pressure if I liked, the gun woud take it, but I declined.
Back then I was able to send the gun myself by USPS, it was an antique. The proof house charge was about $75.00 at the time. However the proof house did not have the correct paperwork to export the gun back to me, they needed an export license, which was free for the asking, but they refused and I ended up paying about $3-400 for a English gunsmith to export it back for me.
