The .45Colt is basically guaranteed oversized chambers. The problem is not the cartridge, it's the SAAMI chamber specs. They're way too generous. Like I said, Linebaugh and other custom `smith's cut .45 chambers much tighter than any factory gun*. The larger chambers overwork the cases, cause velocity/pressure loss and can affect accuracy. Which is why the best .45Colt's are rechambered from something else. A tight chambered sixgun might shoot 100fps faster. Of course, this is not so bad that you can't enjoy a Ruger .45. It's bad enough that I have little use for the cartridge. Which is why I own seven .44Mag's, four .44Spl's, two .44Colt's and only four .45Colt's (two or three of which are going on the chopping block). Not when the .44Mag and .45Colt are so close in performance, yet .44's shoot better out of the box and require no gunsmithing. It just ain't worth the trouble. I've got a Bisley Vaquero that has had all the accuracy work possible, working with a factory cylinder and barrel. It shoots okay but does not shoot as well as any of my .44Mag's did out of the box. If I need more than the .44Mag offers, I'll go up to a .475 or .500. Not a .45Colt.
Don't get me wrong, the .45Colt is a wonderful cartridge and even better when chambered in a properly built sixgun. Hell, I spent all day yesterday handloading for and sighting in my newest .45Colt. I'm just not in love with it like many are. I don't buy any of the business that it's better than the .44Mag.
*(Freedom Arms is always the exception when describing pitfalls in mass produced revolvers)