This is a serious question - but WHY? Is this a personal challenge, a phallic measuring thing/ I seriously want to know as I just got another .308 (Steyr Scout) and want to work up a good hunting load for it. It never occurred to me to try and achieve Mach3 with a .308, I like what another poster said "that is what a 300 WSM is for". The idea of an exotic bullet like a Cutting Edge 100 grain going 3000+ fps does intrigue me, but it follows proper physics of lighter bullet = faster speed. I do love CFE 223 for .308, it has been my go-to hunting load/powder for 6 years using a seriously boring Sierra Gameking 165grain HPBT that has all the aerodynamics of a school bus. That slow-poke round doing around 2600 fps recorded my longest deer kill, a 450 yard shot that went through both shoulders of a nice buck out of a Remington VTR (effectively a 19" to 20" barrel) when you subtract the length of the three slotted muzzle brake on the triangle barrel.
