Re: .300 Win Mag, 180 grain bullet & Retumbo
No, my Sendero likes RL25 with the 180,(3,175fps) which I am sure you know is a tiny bit faster than Retumbo.
I am no expert concerning burning rates, but it seemed I was close to the optimum here.
I will soon be trying the 200 Accubond with the hopes of obtaining 3,000-3,025 or so & I feel Retumbo will be better suited for 200's than 180's, but that is only an opinion.
You will not make peace with the Blue Coats, you are free to go.