[quote author=GTOguy06 link=topic=601.msg4616#msg4616 date=1348688115]
The first one is pretty much a bunch of tables showing how increased barrel length leads to higher velocity. Every inch matters
[/quote]

Any farm boy could have told you that.

But really it also comes down to powder used for the intended use of the round. Take the 44Magnum and 30Carbine. Each round is avaliable in pistols and rifles. Rifle-slower burning powder. Pistol-faster burning powder.