If you think about it, a .410 slug is way undersized for a .45-caliber bore.
Hollow-based Foster style slugs can bump up with ignition pressures, but they're not built for accuracy in a .45-caliber rifled barrel.
Actual slug diameter varies from maker to maker, and can be even smaller than .41 caliber.
The Judge platform is a compromise.
It produces low-velocity results with buck and a rapid short-range spread, indifferent accuracy & low energy figure with lightweight undersized slugs, and generally isn't all that accurate with .45 Colt loads.
It can shoot three different types of ammunition, but not particularly well with any of them.
Denis