Lovely rifle and great to have you amoung us. The winter 2005 "Double Gun Journal" has an article including working up a load for a similar rifle. They settled on 69 gr of 4198, dacron and a 600 gr bullet. My 3" Hollis uses a 610 gr bullet and 70 gr of 4198 and 17 gr of dacron. Where are you in SC? I'm down the road in Savannah if you're ever passing thru.
Best