Re: Sendero 300 Rum load advice
100 grains of Retumbo pushing 180 grain Barnes TSX. Sub MOA groups out to 400 yards, and sub inch groups at 200 yards. The load is lightly compressed, which Retumbo seems to like, I've got 3 other rifles that really like Retumbo when it's a compressed load.
Now I do everything to the brass that I can do, I neck resize, turn the necks, deburr the flash holes, unform the primer pockets and trim to length. I use bushing dies and try to keep the neck tension down to .002, I usually go for less than that, but this thing kicks like a mule and I don't want to mess up the rounds in the mag.