All things being equal an overbore cartridge will wear out the throat faster than its more conservative cousins.

You are correct about "cooler" slowing burning powders. I use Retumbo and Reloader33 in my 338 RUM with a 36" barrel. I am edging 3000 fps with 300 Bergers and will easily surpass it with Scott Null's new 1.0 BC lighter bullets.

It is a 3 groove Nitrided barrel which is so hard and so smooth cleaning is almost obsolete. Shoots 5 shot 1/3 MOA groups to 500, the far most tested on paper. Rings a 12" gong at 1000 with boring regularity.

Scott was telling me of one customer with a custom AR 223, 3 groove, Nitrided bbl who just past 600 rounds with no barrel cleaning. Shot bugholes when new, still does.

How far do you wish to shoot ? "Like no place else on earth."

5 Bergers @400