mrtom,
what are you intending to shoot with it? Big north american species, african plains game or African DG ?
My experience is with the 270 Barnes only, downside is I handload and cant comment on the exact brand and bullet youve asked about.
The 270 gr is becoming more popular with the African DG guys because their terminal performance is exceptional, Ive heard of complete pass throughs on shoulder shots Cape Buffalo which no small animal, now with the 300gr on the books too no doubt that will become a big contender for the likes of Bear Claws etc which are the more traditonal big bore bullets used on DG.
If your rifle likes them and they fit the bill for the game your after (any thing other than DG they will be fine IMHO) use them, I would, they are a good bullet.
All the best
300WSMMAD