I shoot F-Class (F-T/R with a 308). I currently use a Savage PTA with a 30" bull barrel from Criterion. I will soon be ordering another barrel to have ready for when this one dies. I see many shooting F-T/R with longer barrels - many 32" barrels on conventionally shouldered barrel set ups.

My question is this - most of the pre-fit barrel manufacturers list 30" for the max length for the bull barrel. Is there a reason for this? Is the Savage nut configuration not as strong as a conventional shouldered barrel set up? If I have a barrel made to use the nut in a bull profile that finished at 31" am I stressing the action more than if I had one made up with a shoulder and no nut?

Thanks in advance for your thoughts.