I load IMR-4895 in 308 & 243. Have done so for 50yrs. Heaviest bullet I have loaded in 308 is 150gr. For you situation just take load data for 4895 and another brand bullet of same weight, give or take 5gr. Load below max and work up or down for your rifle. Somebody correct me if I’m wrong but the same weight bullet of same diameter regardless of manf. will operate under same load. This may be different for the copper solids and other gimmick bullets on the market. The sales anymore ties bullet companies to powder company, wanting to keep it all in the family.