Max loads for 175's with 49 gr. H414/W 760 in Hodgdon data run 2629 fps, 50,100 CUP/58,043 PSI.
Any idea of pressure to get 2,900 fps (271 fps increase) with 52 gr. H414/W 760 (3 gr. increase)?
The US military picked the M240 machine gun that uses 175 gr. loads at up to 60K psi. Any idea of performance or reliability issues upon increasing pressures beyond 60K psi. Would a 3.0 COAL round work in a M240? Military applications require full auto weapons. The 7.62X51 NATO works real good for military purposes.
The pricy Berger 215, used in a bolt gun, at pressures near 64,000 psi would outperform 175 gr. 7.62X51 rounds fired from a M240.
The US Military has picked the 6.5CM for cartridge/projectile use. Given the choice, I sure would do the same, rather than make the little .308 Win do something it was never intended to do.
My experience with small rifle primers like CCI 450's and ball powder amounts that would be used in .308 loads, showed large velocity spreads, especially a low temperature. 52 grains of 760/H414 is going to need a hotter primer.