I expect you are thinking of the 'Parradox' (sp?) by H&H; supposedly the 'solution' for an all rounder, shot and ball gun. Trials I have read indicated it worked, though I believe there may have been a fair amount of 'fluff' in the copy as the review was not entirely unbiased.
Go to the 'Slug Gun Forum' further down, there is quite a bit about the effectiveness, or not, of rifled choke tubes.