Re: .300 Win Mag, 180 grain bullet & Retumbo
Haven't tried it yet. Probably won't.
I'm using 72 gr AA3100, WLR primer, and 180 Nosler BT with very good accuracy (~1" @ 100 yd [img]/ubbthreads/images/graemlins/grin.gif[/img]) in my Browning A Bolt (no BOSS) 26" barrel "Stalker."
Just bought a chronograph and haven't used it with this load yet, so no FPS data.