I'm going to do a semi custom build 308 win. How would you set it up to get the most range on elk size game. This rifle will mainly be used for practice, but I want to use it to back up my 7mm wsm. I don't mind some weight, say in the range of 12-13lbs all up. Looking for barrel weight, twist, length, bullet weight, type, and stock ideas. After your input, what would you think the max range on a bull elk would be?