I use the 165 Gameking HP in a .30-06 and a .308, at 2800 and 2690 fps respectively, and they seem to hold up fairly well. I was advised by a Sierra Rep that if I had any worries about the Gameking holding together, try the HPBT. So far, they have been doing their job. And accurate, too.
I don't think they would fair so well at .300 mag velocities and close range impacts.
