I've seen a couple of these old (#1 or copies of #1) rolling block shotguns show excessive wear when shot extensively with regular-old-BP-slug loads, not express-rifle type loads. The actions started out nice, but the slug loads just beat the action all to hell. A #5 rolling block might better stand up to the loads, but in the 40 or so years I've been looking at rolling blocks I have yet to see a shotgun built on a #5 action.

For load like you've mentioned, you might consider swapping the roller off for a good Martini action.