The .45acp ctg headspaces on the case mouth, so it would likely slide all the way to the front of the chamber on a .410 if it would chamber at all. The .45 colt head spaces on the rim.
We used to shoot 2½" .410 shells in my Dads old Trapdoor Springfields, but its not really what I call a safe practice. We has lots of split cases as I recall.
I used to have a "recipe" for a load that involved taking a 3" .410 field load and cutting the crimp out and dumping the shot, then seating a .357dia 158gr bullet inside the shot cup, effectively making it a sabboted slug they were for use in the Contender barrels and would develope around .38 special velocities, but .410 rifled slugs will do about the same thing and can be suprisingly accurate from a full or modified smoothbore c .410 barrel as well.
Just My 2¢
GD