Llama bob,
Weight retention has little if anything to do with penetration or the size of the hole as the bullet travels through the critter, instead, it's about frontal area. Smaller frontal area translates into greater penetration, larger frontal areas less penetration. The trick is the optimum compromise between the two--which will never work perfectly every time.
I have to disagree with that first sentence.
Maybe we need to do test. Shoulder shot with standard cup and core like SST, partitions and ttsx and see which one has the largest frontal area and penetrate the deepest into the vitals.
