GG, the .300BO (7.62x35) is, to me, a good round if you want to soup up an AR platform, though the effective range falls off just about as fast as the 7.62x39. Also, though fractionally less powerful than the 7.62x39 for equal bullet weights, it does have a much wider range of weights to use, from subsonic to supersonic (though I stick to 110gr-150gr SS). It's one of those rounds that you either hate or love. Cheers, Bruce.