Every manufacturer of aftermarket barrels has their own "proprietary" contours- there is no industry standardization of dimensions of "heavy sporter", "light target" etc. and they're all named differently.
Take a look at each manufacturers website- Shilen, McGowen, Criterion, etc. They all list their profiles, and dimensions. Some barrels have a straight cylinder at the chamber (usually 3"-4") then a straight taper to the muzzle. Others taper the entire length. Still others have a cylinder, a step, and then a straight taper. Point being, they're all different but the info is there for you.

You don't need to remove the barreled action from the stock to eyeball the diameter holding a tape measure over your barrel, and find a standard contour that comes close for the length you're looking at. You can also interpolate the taper from the manuf. drawing to determine the barrel diameter at any point such as what it is at the forend of the stock.