The 215gr RN is the bullet for a .303 double IMHO, 174gr has military connotations and is just not 'pukka'.
The Speer 180gr RN 'Hot-Cor' projectile is another worthwhile option if relying on modern components. It's a very good killer on medium game in my experience with Lee Speeds.
-------------------- Marrakai
When the bull drops, the bullshit stops!
--------------------------------
www.marrakai-adventure.com.au