Stan, I understand your thoughts, I think. I think the shot is mostly contained in the wad. It must expand to mostly fit the bore and that has to have some pellets in direct contact with the bore. Most likely the shot becomes a shorter shot string in the bore, trading length for larger diameter. Perhaps the choke does have some influence on patterns even in this case. I just have not seen any major difference in how tight the carrier barrel chokes are and pattern performance. As a rule I never pattern a .410 with what I expect to have weak patterns. Plays too many games with my confidence when you see all those holes on paper with gaps here and there.

But there is no doubt that short tubes like Browning Super Tubes and even sidekicks like Briley makes can have serviceable patterns at reasonable ranges. I have not had as good luck with a straight chamber length adapters but they did work at shorter ranges. Breaks on station 4 were weak. Use a set on a good Sporting Clays range and you will quickly find that they are range limited. I have found anything past Skeet ranges just run out of dense enough patterns to be worthwhile and I would never use them on live game. A half ounce or even near 3/4 ounce shot is a very small payload for longer distance use.