I've owned a few of both , and a few Whelens . I currently have a 358W built on a 98 Mauser , it's a really useful little cartridge . Like Hoyt , I've pretty much stuck to 225's ( Nosler Partition and Sierras ) in my 358 and 250's in the 350RM's . They're both great cartridges , but the 350 just has more case capacity and pushes bigger bullets faster . That being said , I've come to like the 358W just a little more than the 350RM , they're both reliable killers on big animals , but the 358 is easier on the shoulder in equal weight rifles , maybe I'm just getting old and soft .