Decades ago, Sierra Bullets never worked up a load fore each bullet's lot number. They used the same powder and charge weight, primer and case, albeit different lots, and shot those same, tiny bug hole groups from their rail guns. My recent contacts with Sierra revealed they still do not work up loads. Nor do they prep cases. Still, as decades ago, their best 30 caliber match bullets average 1/4 MOA at 200 yards.
Try working up to 42 grains of Re17 or IMR4350 under Sierra's .308" 240-gr. HPMK bullet. If you cannot seat the bullet without crunching the powder to fit your chamber, you'll need a longer throat in the barrel. David Tubb shot 250 gr. HPMK's in his long-throated .308 Win. with 42(?) grains of IMR4350, as I remember, he got 2150 fps from his 28" barrel with it. Note you'll need a 1:8 twist to stabilize that bullet enough for good accuracy. Some web sites listing loads for the .308 Win. using that bullet list more powder and muzzle velocity; I'd avoid them like the plague!!!!!!!
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master
Last edited by Bart B.; August 19, 2013 at 07:18 PM.