For fully accurate purposes, I fully agree with you about cleaning thoroughly for each load. It's the only fair way to look at it. We did shoot this gun 4 more times yesterday without a thorough cleaning. Running a snake through twice between each shot. We shot an Apex 1 5/8oz #9 with the Indian Creek .562. And then we shot both Rogue loads, and the Apex load through a HS Undertaker .582 high density choke. As the day went on, the HS printed the highest numbers consistently.
It's possible this gun likes a little dirt in the barrel. But for some reason this gun has always shot amazing with that HS choke. It did with Nitro straight 7's for years and it loved the Apex 9's and the heavy rogue loads. Both were well over 300. That choke also shoots lights out in a Charles Daly youth model we have. It always takes me 15 minutes to figure out how to post pics. But I'll try to attach some later today.