I was reading again today in the Sierra manual. according to them the hp Game king is a tougher bullet that the standard 165 grain Gameking. They claim it is best suited for the 30 caliber Magnums. I have been using the Pro-Hunter bullets in most of my reloading for the last couple years. This year I loaded 150 grain Nosler Partitions and the 150 grain Sierra Pro-Hunter in the 30-06. Last year I had good luck with the 120 Grain Pro-Hunter in the 280' I only load them to about 2850-2900 fps. The Manual says they may be to soft for use at Magnum velocity. I reload as much to down load from top velocity as to try to hop up loads. Many people over drive certain bullet causing them to fail.