I personally won't shoot a deer with a ballistic tip under 150 gr which is what I shoot in 300 WSM. As I said, I have my son shooting Accubonds in his 270, and the reason that he switched was because my brother and Dad have both lost deer using 130 gr ballistic tips. It may be a couple of isolated incidents, but my brother shot another deer that he did find with no exit wound using BTs. It seems that the BTs "rapid expansion" claim is too rapid to make it all the way through our east Texas deer. My Dad has started shooting CoreLoks, and my brother has gone to Nosler Partitions. Neither has lost a deer since switching.