Bob,
As I attempted to point out in the article but perhaps didn't quite make clear is that there's something of a continuum in bonded performance--in particular among the thicker-jacketed models. The basic principle is that the less lead inside the jacket, the deeper the penetration, due to a smaller mushroom.
The very first Trophy Bonded bullets opened up quite widely, like the Bitterroots. But as they've gone through a couple of generations of modification by Federal, they've been modified to leave a small mushroom, partly by modifying the jacket but also partly by reducing the amount of lead in the front of the jacket.
To tell the truth, I wasn't all that crazy about the originals, at least in the typical calibers used in North America. They tended to open fairly widely, but with a rounded mushroom that didn't do as much internal damage as the wide, winged mushroom of the Bitterroot or Norma Oryx. The solid copper shank also tended to foul the bore, like the original X-Bullet, and accuracy could be iffy, depending on the rifle.
Federal's first modification changed the frontal jacket gemetry to result in a flatter mushroom, which seemed to kill better, in my experience anyway. They also used gilding metal instead of pure copper for the jacket, which (again in my experience) helped. But some people didn't like this bullet as much, in particular some African hunters who used larger caliber TB's. They found the wings of the mushroom sometimes broke off, for one thing.
The Tipped Trophy Bonded has solved the solid-shank problems, and also seems to have a little less lead, increasing penetration--which seems to be the 21st-century criteria for premium bullets.
The North Fork may have been originally designed as another semi-copy of the Trophy Bonded, but it works more like a Barnes TSX, due to the tiny amount of lead in the tip. Norh Forks penetrate deeper than any other bonded bullet I've used, due to their relatively narrow mushroom.
