KKSP were good bullets for shorter range shooting. Perfect for 30-30 class hunting but in say, 30-06, one wouldn't choose them for mountain hunting because being blunt, they cutdown the practical range of the rifle.
It's not right to refer to them as "Imperial." Canadian Industries Ltd. made the amunition in Canada, with various further name designation. They called it Dominion ammunition, then further classified it, or at different times used different names for basically the same ammo. In their later years they used the name Imperial for some of their ammunition, both rim fire and centre fire. KKSP were not associated with the name Imperial.
I have said on here quite often how I thought the Dominion CPE, copper point expanding, was a great hunting bullet. In my opinion it was as good as a Nosler partition, and may have even retained more weight, than does a Nosler. They were also perfect for longer range shooting, because of their shape, which was just like a military fmj.