Woodleigh monolithics ... 450gr and 400gr. Today I received the 325gr 45cal monos for the new project rifle. A 458WinMag equivalent from a short action.

I can't remember BGRC rules ... I think you can get away with a 400gr projectile though, but it's not exactly factory equivalent. Bertram makes a 480gr-500gr projectile in 458" that's cheaper than Woodleigh.
Cheers...
Con