Re: 7stw or 7rum w/8 twist
I had a bad problem with extreme throat erosion with the 7mm RUM. I think the 7mm STW is about the best you can do in 7mm before reaching an extreme barrel burner. I got excellent velocity and accuracy out of the 7mm RUM, just no longevity. I don't have my notes with me but I think on average it was right at 120 fps faster than the STW with 175 grain bullets. 120 fps was not that important to me compared to replacing barrels often.
Predictions are difficult, especially when they involve the future