I have always wanted a big bore fowler and finally acquired one. Just thought I would post the proof marks as they are so unusual:

[Linked Image from jpgbox.com]

Damascus barreled 36" single 8 bore (1878). Not every day you see a 3 1/4" chambered gun proofed for 2 1/8 oz of shot! Weighs about 14 lbs. I have yet to measure the choke. Barrel walls are massively thick.