Re: 7 STW
I had mt best luck with H1000 & Retumbo when using the 160gr bullets in my 7STW. However, I haven't tried the 160 Barnes bullets yet. The X bullets are a horse of a different color.
In general, I have found that the X bullets prefer powders that are not the slowest burning within the list of appropiate powders for any particular cartridge and bullet weight. Just my observation.