Daryl,
Another excellent post. Thanks. I was aware that you were speaking of the OS card flying out of the way at the muzzle. Have read W.W. Greener several times but need to review that part about the roughened muzzle and a heavy wad pushing up thru the shot charge in a cylinder bore.

But I am embarassed to say after a gazillion shots patterned out of old cylinder bore MLs that what I was referring to was photographs of MODERN S.G. loads which did not have the wadding moving up thru the shot as a cause of doughnut patterns. Since my overloaded brain was not putting two and two together that a cylinder bore has nothing to retard the wadding, and that it it now known that a major reason modern chokes work is precisely because they DO retard the wadding, it makes perfect sense that the heavy, lubed fiber wads would not do well in an old ML and instead the lighter wad columns do better. Exactly what I have found, as mentioned above.

But just go to any ML S.G. shoot (trap, etc.) and watch most competitors cheerily loading cheap, home-lubed fiber wads down their cylinder bore guns, often having little idea how they pattern!

My stacked wad columns trying to get a good gas seal in old pitted bores are not that light in total, but the fact they are made up of 3 or 4 separate wads may well allow the wads to blow off to the side and not up thru the pattern. It also would substantiate my finding that loads using polyester fluff in the wadding are usually quite good.

I don't think I am going to roughen the muzzle area of my old shotguns for value reasons (definitely going up on this side of the pond at least), but highly recommend the light wad trials.

Now I'm off to my 9th Ed. of W.W. Greener's "The Gun and its Development". ( A must read for later-era-BP enthusiasts, and now back in print!)

Aloha, Ka'imiloa