Shots,
You are in need of some help. If you have a Holland Paradox, the original maximum case lenth would have been 2 3/4", even in a nitromagnum. Alloys used in a paradox should be no harder than 16 to 1 and bullets would have weighed in at 730grs or a tad more. Donot use modern slugs in your rifled choke paradox. What is the # sequence of your gun? There are loads using Unique and other shotgun type powders but you first need to ascertain just what load your gun was proofed for. You can PM me if you like.