The reason you don't recover TSXs is that they barely expand (and at many velocities DON'T expand). What really matters for penetration is expanded SD, so they penetrate just fine.
What they don't do so good at is width of wound channel. I've seen more well-shot game lost with TSXs than any other premium bullet.
The advantage of a high unexpanded SD is that you can have your cake and eat it too if the jacket thickness and weight retention are suitable - a wide wound channel AND a deep wound channel. That's the strength of bonded/soft core high SD bullets like the heavier Weldcores. Their wound tracks are ideal. You can't get that with a low SD bullet - you can have one or the other but not both.
Have you recovered said TTSX that expanded and didn't expand?
He probably hasn't. In most instances when I see statements like his, when I ask follow up questions I hear things like, "The exit wound looked like a pencil poke". What that usually means is that they are so used to seeing baseball sized exits from cup and core bullets that come apart inside an animal, that when they see an exit from a bullet that actually holds together, they believe it "didn't expand".
Also, how can he claim that animals that were lost were "well-shot". If you didn't recover them, they were not "well-shot". I have yet to have a "well-shot" (i.e. both lungs, heart, or CNS) animals go more than 150 yards from impact to crash. The only ones that went over 50 yards for me were already amped up or were going downhill. I have had animals go farther, but I am not going to blow smoke up your butt and tell you that they were "well-shot". Did they die? Yep. Were they "well-shot"? Nope.
