Did you every get your 338 Norma inproved done ?Presently building one with 35 deg shoulder will let you know how it performs after testing.
Ken
The Norma is more efficient because it's shorter and fatter than the Lapua. Think of it like a 7mm SAUM compared to a 7mm Rem Mag. My 7SAUM will match my 7RM but use less powder and easily fit into a short action.
As LTLR stated, I dont think that you are going to reach your mark with the Norma. As he mentioned the Weatherby or the 338 Allen, the Norma has less case capacity than the lapua 107 h2o. I had pressure signs in my norma at 2840 w/300 berger.I am going to try the Hornady 285 gr. think this might be a better fit for my lighter rifle.
actually, the saum cant hold a candle to the rem mag.... just sayin, it looses about 200 to 300 fps............... do your reasearch first, trust me i have, i was thinking would the time advantage in a short action be helpful on a spooked deer, or would i want the range and slap the the rem mag has so i have a better chance of putting him down at longer ranges if i can still see him...