Hi Jacking Warning!!!!
Could Sooner use 454 or 460S&W cases, keep loads at regular 45LC loads with a dacron filler to help?
I had a 410/45CL barrel with the survivor stock/forearm and really liked it.
BTW, I wold say no more than $40-50 for a drill and tap WITH a weaver rail. That the LGSs around here charge, rough estimate is $10-12 a hole. And the rails are under $5 by themselves.
Personally, I would add a peep and ramp front sight. More expensive for the sights than a cheap scope and rings. But could do a folding down rear (think Ruger 10/22) and a dovetailed front. Either can be readily used for the 410.
Afterthought, I had an old Stoeger 410 single shot (full/adult size that I was told the type the company gave natives in where ever they had their factory) that was 28" lightly modified and would shoot 1" groups at 25 yards with 2.75" slugs. Took several small does with this smooth bore. Paid $45 for it and then took it to the LGS and told the GS I wanted it with sights like a modern day trade gun. I had a few back issues of The Backwoodsman and showed him the setup. We both agreed it was a cool idea! After a few minutes of digging through a couple of boxes of old used front and back sights, found some that would fit the contour of the barrel and a match in high. Couple days later and $35, picked it up and three boxes of 410 slugs and went to sight it in. Awesome project! Think it got lost int he divorce, cause was given to BIL to use a couple of years before it got bad. Doubt I would ever see it again.
Lefty