Tenon= threaded portion of barrel that resides in the reciever.
Shank= is the diameter of the initial straight section ahead of the tenon.
Remington has one tenon size 1 1/16" and the barrel shank can be up to 1 1/4"
Savage small tenon are 1 1/16"
And large tenon are 1 1/8".
Savage barrel shanks tend to be the same diameter as the tenon due to having a barrel nut. However, when not using a barrel nut, the shank can be 1 1/4"
Shank length - We tend to like a 5" shank length before taper starts. So, a barrel with a 1 1/4" shank 5 "long tapering to 3/4" at 28" could be turned and threaded for Remington, Savage small tenon, or Savage large tenon and be equally strong in either one.
The gun that KPH has is a single shot conversion with a match grade barrel. They are limited on shank size to right around 1" due to their design. This is why it is advised to refrain from shooting hotrod loads in them.
Obviously, a larger shank can handle more pressure before failure.
My pressure test gun has a shank diameter of 1.385" and a 115,000 psi load swelled it .005" right behind where the bullet sits on the powder. That same load would have made a 1" shank barrel look like a pealed banana.