I also have the 7mm mag. I think the twist is 1:10. I don't load the 150gr. I have loaded the 145 Barnes LRX bt and the 139 LRX bt. I will have to double check what I was using. I think it was RL-17 with a CCI 250 primer. I took a NM Pronghorn at about 460 +/- last year.

I got a Hogue stock for my Savage 300 WM and feel that it has increased the accuracy greatly. I am in the process of getting one for the S&W 1500. Can't wait to see what it does.