I don't shoot ,30 Caliber any more but here is a great article by Brian Litz on your 155 Lapua. By the looks of it, I'd sure give it a try. Brian is the Guru from Berger and really knows his stuff.
http://www.appliedballisticsllc.com/index_files/Lapua_Scenar.pdf
Edit to add link I forgot.
http://www.appliedballisticsllc.com/index_files/Lapua_Scenar.pdf
Edit to add link I forgot.