OOPS. You are correct. I got my threads mixed-up.
Hornady does make LEVERevlolution ammo for the .44 magnum, so what I wrote in the previous post still applies to those cases, although perhaps with some modification for a different case length for their shortened .44 Magnum cases.
For the .45 Colt, the the case is 0.041" too short instead of 0.050" too short.
According to QuickLOAD, working with something like Unique to produce 14,000 psi loads with a Hornady 250 grain XTP, using the shorter case increases pressure by only about 1,000 psi.
If instead, we use "Ruger only" loads of 2400 at 32,000 psi, then using the shorter .45 Colt case gives an increase of about 3,900 psi.
With a 300 grain bullet, the increase goes to 5,700 psi with 2400 in "Ruger only" .45 Colt loads. I am sure that something similar would happen with 300 grain bullets in the .44 Magnum.
So, I guess the point is that the length change isn't too much problem with SAAMI loads in the .45 Colt, but could be with magnum level loads in this or other cartridges.