SOOOO------how are you dealing with the "destructive device" issue?
USC title 18-921
(4) The term “destructive device” means—
(B) any type of weapon (other than a shotgun or a shotgun shell which the Attorney General finds is generally recognized as particularly suitable for sporting purposes) by whatever name known which will, or which may be readily converted to, expel a projectile by the action of an explosive or other propellant, and which has any barrel with a bore of more than one-half inch in diameter;
There are already few enough people who buy the S&W .500, and vastly fewer who can even handle it when loaded to its full potential. I think it would be more of a novelty gun than anything, just like "yeah, I've got this big gun," heh.
Now, build a Circuit Judge to accept .454 Casull as well and I'm sold :P .