Up till a few years ago I thought the main barrel makers had all gotten together and figured out a "standard in barrel profiles" and labeled them A,B,C,D, to help lessen the confusion and make it more convienient when you buy a kit because you'd then be able to buy any barrel you choose and have it fit in your precarved kit. Sadly, such is not the case. A "C" weight Colerain isn't the same as a Rice which isn't the same as a Getz. Why they can't all get together on this is beyond me....
And, I've noticed in the past couple of years , some barrel makers don't hold tolerance on their barrel profiles. I just had to practically hand inlet a barrel into a kit this week because the barrel was so over sized and out of spec.