My fire formed 6.5X47 Lapua cases, hold 48.8Gr's of H2o.
a 30X47 Lapua makes for a very competitive HBR cartridge.
Gary, the weight limit for a hunter class rifle with scope is 10 lbs and stock fore end cannot exceed 2.250" in width. You can get all of the requirements by going to the benchrest central web page the click on the IBS logo, then click on the download tab and download the IBS rule book, that way you can make sure your build meets all requirements. I started shooting Hunter class back in the early 80's and Remington actions dominated the field, today there are a number of custom Rem clones that would probably work better, just food for thought. Good Luck.