You 7mm experts, please advise: What's the difference b/w the 2? I'm looking at another rifle maybe to put together next year. I sure like the thought of getting 300WM brass and necking it down because I've seen and read all about the difficulty finding STW cases. If both had a 27" barrel with a 180 VLD bullet, what's the difference? Is it substantial? I don't know squat about either.