"Ten shot groups don't necessarily have to be fired fast enough to overheat the barrel."
I guess that depends on where you're shooting. Much of my load work ups and test shooting takes place in the summer, many times with 110+ heat. The barrel can already be overheated just by being in the sun. Two of my rifles are chambered to the .270 Win. and have barrels that are soda straw thin. One shoots sub MOA and the other is an unknown regarding accuracy. So far it does about 2.5" using the iron sights which is about as good as I can do with my 84 year old eyeballs. The rifle is Danzig Mauser WW2 bring back and the original scope system was removed by a previous owner. Interesting thing about the rifle is it has a barrel that is extremely thin and has a stamp that says P.O. Ackley. My gunsmith recently retired DAMMIT! His estimate to do the bolt handle and rework the receiver was somewhere between $700 and $1,000. There are 8 screw holes to be filled in, then drill and tapped fo a scope mount. There is also a "pit" in the receiver ring about 1.8" deep that has to be filled in and recontoured, plus another on the rear receiver ring that is about one inch square that has to be filled in. Really it all mostly labor costs. All that work to clean up some kind of Mickey Mouse German engineered scope mount. I wish I could do pictures. I might have gotten lucky and found a proper scope mount for a hell of a lot less money. One thing I do know. That rifle with 24" soda straw barrel weighs about 6 pounds without a scope. The other rifle in .270 with a soda straw barrel weighs 7 3/4 pounds with scope, sling and full magazine. It too has a 24" barrel. It's pleasure to carry. It has a few deer to its credit.
PJ
