BS,

If you know, what are are the band diameters of the ordinary Maxi-ball? My groove diameter is .510. Land diameter .501.

Your gas seal arrangements are almost identical to those I planned for the 410 BB, the only difference, rather than buying the sub-bases right off, I was planning to use somerecovered Powerbelt skirts or sabots minuspetals, under the wads to see what benefit the plastic contributed over-all. What benefits over the "wad only results" did you see?

I really like the idea of the plastic-wad combination. Thinking the wad will swab the barrel each loading, and the plastic help to prevent powder contamination. I'm looking forward to trying it.

Happy Hunting, Phil