dgludwig, please take a look at the link I posted earlier... some convincing data there.
Well, Zombie Steve, I found the data you referenced interesting if not convincing. In an attempt to not stray from the intent of the OP, I based my assessment on
factory loaded ammunition. And in that context, I believe the .44 Magnum/.44 Special to be more versatile than the .45 Colt.
And, yes, when it comes to ballistics, like physics, there's no free lunch. To increase performance you've got to boost pressure. When all other things are equal (barrel length, bullet weight, etc.,), it takes more powder to drive, let's say, a 250 grain bullet from a 45 Colt faster than it takes to move it slower. More powder, again, everything else being equal, means more pressure. More pressure results in the bullet moving faster.
But...I'd be the first to acknowledge that Mr. Linebaugh has far more knowledge than I do on this subject. And, because I like to think that I have a somewhat open mind, I certainly will give more thought to my position on the matter.
Anyhow, I have no partisan interest in the discussion, per se. I own both calibers and would hate to do without either.