The 270 will kill elk with good shot placement on a broadside animal. I would not use 150 gr. Core-Lokt's. There are many controlled expansion loadings on the market today. Look for Federal Premium loaded with the Nosler Partition, Barnes X, or Trophy Bonded bullets. Winchester offers the fail-safe for the 270. There are numerous others but any mentioned should work nicely. Also, go with 140 gr or heavier.