Well, in the interest of being a bit more clear --
if you take some low-buck slugs with thin jackets that were built & designed for 800 fps from a .45 Colt and you violently flung them from a .460 Mag at 60k PSI and over 2,000 FPS, you run a very
real chance of damaging your revolver by running bullets way, WAY out of the scope of their design & construction.
The opposite isn't true. You won't hurt your .45 Colt by running those high-performance (and expensive!) slugs through them at a loping .45 Colt pace.
I just think they are better saved or swapped or even sold for something you can use. I doubt Hornady would warn you that it's unsafe or unsound. In fact, in some of the big, beefy .45 Colt guns that folks run hotrod .45 Colt "Ruger & Freedom Arms ONLY" loads through, some guys are maybe even running those bullets or something similar.
What's the firearm you hope to load .45 Colt ammo for? If we are talking a nice fixed sight CAS-style Single Action Army replica, than I just don't see the point in running these slugs. But if you've got a big, bruising Super Redhawk or something on that order -- hold on to them and run 'em full-nuts in a while after you've gotten your feet wet in handloading.