Two of my favorite loads:
250gr LFP or 255gr LSWC and 8.5gr Unique.
This is a great general purpose load and has been very accurate in my guns.
300gr LFP and 10gr Unique.
This is a +P load and your Ruger will digest it with no problem.
Yeah, you can work up some "magnum" level loads for the Ruger. The question is do you really want to? The .45 Colt is an outstanding cartridge just as it is. It will take deer sized game at reasonable distances without all that noise and recoil. That is exactly why I prefer it to the .44 magnum. If you want magnum power, buy a .44. Otherwise you'll find the .45 Colt has plenty of power without the pain. JMHO.