What sought of speed are you looking for?

I dont think the 416 ruger was designed to do much more than 2400fps with a 400gr bullet which is a what the 416 Rigby was renowned for.

I have been experimenting a bit with AR2206H powder and the last 5 shot groups with 340gr Woodleigh bullets and 80grs powder averaged 2584fps and with 400gr Frontier bullets and 76 grs powder averaged 2361fps.

These were just the first loads using this powder and there was no pressure signs in fact I was able to seat the 400 grs in to the cannelure for the first time which was impossible when loading with AR2208 due to compressing the powder too much. This was in my 20" barreled ruger Alaskan.