You'll be able to get some great velocity out of the 7WSM if you throat a chamber long with that LA mag. The new 195gr Berger EOL bullet is coming out soon, and that would be an absolute missile from the 7WSM at 2900+fps, with a predicted G1 BC of 0.794
Can't go wrong either way, but if you're pushing it to 1300+ yards, I'd probably neck down Norma .300WSM brass to 7WSM and go.
