Used to be a SASS annual match in Missouri that featured a similar stage. It was similar to a GAF stage, because it was "engage all the targets with whatever gun you wish". I expect Drydock has shot there too. I was shooting BP, with 2 1860s, a '66 carbine, and double barrel shotgun. When the pistols were empty, I commenced firing with the '66-until the carrier block jammed after about 4-5 rounds. After that, I can assure you that a double barrel Stevens 311 gets REALLY hot with extensive BP shooting.