To reduce loads in my 500-450 #2 a member gave me a tip to use amaranth seed filler between the powder and a single under bullet wad. It is very hard and light, meters like a ball powder and passes the compression on between the wad and the powder. Since the 500-450 is a BN, out of caution I only use what fills the straight part of the neck which wouldn't matter in a straight case. That is, only where you could use a stack of wads.