Sorry, but I just can't believe that the .375 and .416 Nosler Partitions only retained 35-40% of their weight, unless the .375's were older ones--or maybe 260's.
I have recovered quite a few of those (as well as 9.3 286's) from game and the LEAST amount weight retention was around 85%. That was a .416 that entered the left rear ribs of a Cape buffalo and ended up in the shoulder on the other side. All the others have retained 88-95% of their weight.
The least amount of weight retention I have seen from any of those three Partitions is about 75%, from a 9.3 286 that was shot into dry newspaper at very close range. It lost all of the front core and most of the peeled-back jacket. But even if you hacksawed all of a 9.3, .375 or .416 off right in front of the Partition it wouldn't lose 35-40% of its weight.
I have also tested the heavier Nosler Partitions against Swift A-Frames in dry newspaper (a more realistic test than plywood, steel, oak, and conveyor belt) and the Partitions have out-penetrated the A-Frames--usually not by much, but they did.
The A-Frames retained more weight (though again not by much) but opened up wider, the rear and as well as the front, the reason they didn't penetrate as deeply.
In fact even when I have tested Partitions and A-Frames in smaller calibers, where the Partitions DO lose about a third of their weight, the penetration has been very similar, because the A-Frames open up into a wide ball.
