Hevi-Shot may offer some interesting possibilities in the future. At present the shot is very expensive. We will have to see.
The other interesting factor is its weight. Pellet count per ounce is less than lead, but the additional weight could pay off in downrange energy.
As for after-market chokes.....some are good, some are not so good, and some are a joke. My brother has a Comp-N-Choke that he is pleased with when using #5 shot. There is two different ideas for AMC's...One is super tight constriction, which works on the small, very hard pellets. The other is the Wad Retention Theory....That the choke grabs and pauses the wad, letting the shot move out undisturbed. My Specialty Shotshells work in this type choke, as well as the regular choke tubes and fixed chokes.
All of the present factory offerings will work well out to 40 yards (most of the time)!!!!!
#6's will break a neck at maybe 40 yards, but for those body shots out at 50 yards, they can't hump it.
Remember, it's not the amount of shot in the shell, but rather the number of heavy shot hitting a 10" circle at 50 yards. I can build a shell that will fill up that circle at 50 yards with #6 through #8, but will it kill cleanly. Would you shoot a Canada goose at 50 yards with #6's?<!--emo&???--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'><!--endemo-->?<!--emo&???--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'><!--endemo-->? I think not and a tom turkey can weigh more. So.....shooting little circles in a shooting game is much like a card shoot.....a game.
Best Regards, James