Ted,
Heavy cardboard was only used for the Barnes at that time, and it was to back the target sheet. When testing, I usually place a 5/8" plywood and 16" / 18" of silicone (made in tube shape) behind, plus wood dust as a last stage to stop the bullets (and ease reCovery).
The PPU is OK, and keeps together as long as it doesn't thumble after impact.
The Hornady I tried stayed together, they do not tend to thumble much, because of the nose shape, maybe, but I did not make extensive trials. I tested a pretty large array of bullets and they stayed together pretty well.
Shoot a large moose at about 60 meters with the Speer and it just went through like better, hammering the beast like if it was hit but thunder. About 50 feet behind where it stood, I saW what, for a moment, I thought was a half round spray paint spot in a birch. In fact, it was a half-round, about 7 inches diameter, of blood and hair and lung tissues... never recovered a bullet from games I shot with the 9.3X62.
9.3 Mauser,
You can't go wrong using Woodleigh bullets.