TC1
I didnt test the two you mentioned, but the 300 RUM , I tested with H870 and H4895. Same results as a 308 or 223 or any others. In my opinion and testing, modern smokeless gunpowder burns like modern smokeless gunpowder. No amount of case shape, advertising, endorsements, etc, has any effect. Dont take that as the gospel, thats just what the chronograph and strain gages tell me.
Charlie