Obviously new to the forum and looking to build my first long range big gun. I live and avidly hunt out west. I recently built a .257 WBY for 400lb. game and smaller. I had been using a stock Remington 700 LSS .300 WSM on larger game. Although it shot well I wasn't really happy with the rifle. I considered making it into a 6.5 WSM for a short time but since the .257 WBY was already in the works I decided to sell it to a buddy that's a little less picky than I. So here it goes... In my own research I'm leaning toward something in the .338 caliber range due to there higher BC and heavier weights. (however I'm open to other suggestions.) I think I like the idea of starting with a Sendero platform. My first thoughts were building a .338 Edge from a .300 RUM. Than I started reading on the .338 RUM. From what I can tell its just makes more sense to buy a .338 RUM if that's the ballistic performance your looking for. However they don't make a sendero chambered in .338 RUM. Like I said I am new to the long range thing and defiantly open to other suggestions on rifles and the best way to go about building a good platform. This seems to be the place with allot of good folks to point me in the right direction. Thanks in advance, Speedy.