My reamer works just fine w/ 270 brass and a no turn neck. I am not a gunsmith but would trust my 'smith with my reamer. He does do blueing, but I don't know if a Win 70 is one of his favorites. I have never done one as the extractor notch and coned breech always scared me away.
PM me if you want his phone #, to talk to him about doing it on a Winchester
