Duff,
The way I understand things is the Savage rifles have two thread diameters, 1.0625" for standard rounds and 1.115" for the RUM rounds.
With the larger diameter of the RUM barrel threads they had to thin the locking nut quite a bit until now they have been having problems with the nut splitting at times, especially if overtightened.
This was the main reason I will fit my 270 AM in the Rem 700 fashion.
There are also other factors. I like a heavy barrel shank of 1.250" diameter over the much smaller shank on the Savage rifles.
I also believe it is much easier to true up the critical surfaces of a rifle fitting the barrel in teh same manor as the Rem 700. These surfaces are the Receiver face, the rear surface of the recoil lug, the front surface of the recoil lug and the barrel shoulder.
It is very difficult to true up the barrel lock nut baring surface. SOme say there is no need to but as an accuracy nut, I just have to know that all the surfaces are true.
Also, the barrel nut raises hell when bedding rifles. Its not a huge deal, you just have to allow clearance so it does not touch anything. I do the same thing when fitted to the Rem 700 fashion but its much easier to do with a smooth barrel compared to a barrel nut with grooves running lengthwise.
Finally, I like to torque my barrels to around 60 to 65 ft/lbs. Only 40 ft/lbs is recommended for the Savage system which on most instances I believe works fine, I just prefer a little more with larger magnums. Plus getting rid of the barrel nut eliminates the chance of this nut cracking which can result in some pretty dramatic damage if not noticed right away and the rifle is shot in this condition.
It looks better in my opinion as well, cleans up the lines of the rifle giving it a classier look.
Mostly personal preference but there are some critical reasons for this.
Have a good one, that little 308 should be a great shooter. Do not worry about the barrel nut on your 308, the cracking problem is only with the RUM rounds as far as I have ever heard.
Good Shooting!!
Kirby Allen(50)