Re: 6mm rem Ackley. 1-10\" twist 26\" barrel anyone have info.???
Got one. Mine is a stainless Shilen #4 on a mid 70's Weatherby Vanguard. My first wildcat. If I had it to do over, I'd do it in 6mm/06. I used up probably half the barrel life forming cases and finding a load that would shoot...
Have you thought of 300 H&H?
Looking at Hogdon's data, you'd get 90% of RUM velocity with 80% of the powder. May not double barrel life, but it is a cartridge with a pedigree.