Some of the old double Express rifles were also bored out. I did have a W.Richards double .450 that was bored out to 20 bore. The rear site was removed and a section of rib soldered in and re-cut; not quite invisible but still hard to see. I've never seen a rook rifle with hammer bolts although my 20 still had them. Might have been a .360 Express rifle then made .410 which would make sense. Lagopus…..