What were the numbers given? The baddest 6.5mm out there is Mr. Allen`s 6.5 Allen Magnum, based off a .338 RUM Allen Improved. Im not sure you could get much more velocity than what that gets, regardless of the amount of powder used. He takes it to the absolute most powder you can stuff down a given bore size while still getting velocity gains, taking it any further than what Kirby Allen does with his Allen Mags will result in dramatically diminished returns for all intents and purposes. For example, his .257AM gives +500fps over the .257 Weatherby and +200fps over the .257 STW! And as you probably know, the .257 STW is based off the 8mm Rem Mag, a massive case with quite a small bore. With the .257AM, youre talking about 100 grainers at 4050fps!