Great post. NICE bull. Congrats to you both.

I"m in the camp of the guys who are surprised at the performance of the Partition. I've been using Partitions since about 1980 in both 270 Win and 300 Win Mag. I've never been disappointed with the performance I've gotten. I've only recovered 2 and they displayed perfect behavior.
I suspect there may be a flaw of some kind in that particular bullet or batch, possibly the jackets.
I'm of the belief that no matter what make of bullet you use, at some point you are going to hear about someone being disappointed with it's performance. When you think about the literally millions of bullets made and shot in the world over the course of a year, I think all the manufacturers do a very good job of putting out very good bullets. In the scheme of things, the few bullet failures that happen are quite miniscule by comparison. I know that is no consolation if it happens to you. Has your buddy shot any other game with that bullet?