Brasso, all indications are that a bone-stock .45LC Ruger has more raw power potential available, with heavier bullets, than the .44Mag.
What you really need to do is go to John Linebaugh's site at
http://www.sixgunner.com/linebaugh/ and look at the articles he's written on the left-hand column.
The hottest factory .45LC I'm aware of is the Buffalo Bore, 325grain pulling 1,300fps from a 5.5" tube. That's past .44Mag specs, by a hair.
What Linebaugh explains is that the .45LC case volume is really "too big" for modern modest-power loads, but you can make it work OK. What you REALLY need to do is fill the case, or close to it, but that means slow-burning powder like H110. If the bullet starts down the barrel too soon, that slow-burn powder hasn't had a chance to fully "catch" and then performance suffers, velocity starts to vary, life isn't good. So you use a heavy bullet, something over 300grains, and it takes a fraction longer to "get it started"...which gives that H110 time to "catch".
The other result is that the blast happens over a greater time period than it otherwise would using a more conventional .44Mag recipe involving a 240grain at 1,450 or more. So the "felt recoil" is more reasonable in the .45.
That Buffalo Bore load is really towards the BOTTOM end of the scale that's within this Linebaugh-type load technique. Which is fine for the factory cylinder, which is tough but sometimes a hair oversize on the cylinder bore which doesn't seem to impress Mr. Linebaugh much. Linebaugh describes loads such as a 345-grain doing 1,500fps from a SIX shot oversize custom cylinder
.
See also the bottom/middle dead critter pic on this page:
http://www.sixgunner.com/linebaugh/game.htm - click the pic for the text.
Granted, today he'd prolly recommend that load with a 5-shot cylinder but still...damn! And that gun didn't even have the Bisley grip frame, it wasn't available then.
Sooo...given that Buffalo Bore recommends it too, I'd say their 325 at 1,300 in a bone-stock gun should work
.
And that's past .44Mag spec.
You could run heavier bullets and back off the speed some and still get great results. Probably out to 400grain at 1,100 or so? That's handload experiment time...me personally, I can't see needing more than that 325 at 1,300.
What else...read THIS first:
http://www.sixgunner.com/linebaugh/penetration_test.htm
Look at what they got out of a modern-type (like Buffalo Bore's 325 versus Keith-type) hardcast 300grain doing 1,180fps. Ask yourself how much more you need
. Also note in the text reports of loads going "too fast" and shattering before breaking the shoulders of a now-pissed buffalo
.