Count this one among the beginners questions ...

I've seen a lot of references to "barrel profiles" and have deduced (at least I think so)that it's the diameter at the muzzle that determines the profile. But what's a #1, #2 etc?

For example, my 6,5 Swede has a muzzle diameter of about 0.6" with a 23" barrel and my 375 H&H is 0.75" with a 25" barrel. What are their barrel profiles?

Each barrel manuf. has a list of contours along w/ their measurements. Pac-nor.com is but one example. They are numbered from #1 being lightest to #6, #7, etc. being heavier.

I see, theres no common scale. I noticed that the barrels mentioned above are a #2 and a #6 going by Pac-Nors scale.