Am building a 7WSM in the near future and am wondering what twist to get in my barrel. I currently have a GAP 7WSM and I think the twist rate is 1-9. I've noticed a lot of builds now are using 1-8.7. Is there some kind of advantage to this faster twist? I'll be shooting 180 Berger VLD's in a 28" barrel and plan on shooting out to 1500yds+