And you perfectly illustrate the conundrum with premium bullets- Bullets such as Accubonds and other bonded core bullets make nice, pretty mushroomed bullets with a large frontal area. However, these bullets have the potential to lose penetration because of the increased frontal area. John Barsness of Handloader magazine very succinctly illustrated this by pointing out that as a bullets frontal diameter increases, its sectional density effectively decreases. In other words, a .30 caliber, 180 gr. bullet with a pre-expanded sectional density of .271 that expands to a diameter of, say .60", would have a sectional density of .071. The other end of the spectrum of premium bullets are those such as the Barnes TSX's which expand with a smaller frontal area but penetrate more deeply.
Just some food for thought.
35W
This is definitely among the things to consider when selecting a big game bullet. There are always trade-offs; everything is a compromise. Bonded bullets are much tougher than standard cup-and-core bullets, but they do, as you say, mushroom and expand more than monometals like Barnes' TSX. The trade-off being that you do get more expansion, and potentially more wounding as the bullet works through the animal, while still getting enough penetration for big game. In my mind, the Accubond exists in a balance point between monometal (e.g. TSX) and cup-and-core (e.g. ELD-X, SGK) bullets in terms of terminal performance.
Federal's Trophy Bonded Tipped (and the newer Terminal Ascent) is something of a hybrid between a "regular" bonded bullet and a monometal. It has a solid copper shank and a lead core only in the nose of the bullet, and that lead core is bonded to the jacket. It's very hard to find these as reloading components (I had some factory second Edge TLRs a few years ago from Midway, but otherwise I've never seen the federals in stock as a reloading component), but I think they make a good choice if you're shooting factory ammo and your rifle likes them well enough.
I have a few pictures of the TBT bullet we recovered, but the ones I have handy show the bullet covered in blood and hard to see. I have a clean picture some where but I can't find it at the moment. It looked very much like the picture of the Barnes you posted, however. The solid shank was intact. The nose had expanded and there were copper petals pulled back, though smaller and more compact than your picture. One side was mangled, probably from hitting bone, but the other two were not. Interestingly, the lead core in the nose was almost all gone. There was a little bit still attached to what had become the front of the expanded bullet. The rest had apparently been "swiped" or "flowed" off the bullet as it passed through the animal (my words to describe it---not jacket-core seperation---picture what you see with Accubonds). The TBT did exactly what it was supposed to do on an imperfect angle, and we recovered the bull less than 100 yards from that spot. But I was surprised the bullet did not exit.
As you said, there's food for thought. Would my Accubonds have held together as well as the TBT did on the same shot? Probably not quite as well. I think they would have still worked just fine, but the TBT losing almost all of its bonded core gives me a little pause, although those bullets don't have a whole lot of lead core to begin with. Add to this pause an experience I had one time where my 180 Accubond didn't exit from a whitetail deer I shot in the shoulder. A very short range shot from my 30-06, and probably a fluke, but it still happened (deer fell over where it stood, but not what I expected from the Accubond). That prior experience lead me to play with Barnes' bullets a little bit. I tried to develop a load with 168 TTSX bullets, but I always ran into pressure before I could get close to advertised velocities, and my accuacy with them in my rifles has ranged from not great to just so-so. I can run 180 grain Accubonds about the same speed as the 168 TTSX bullets, and the Accubonds shoot better in my rifles. That's why I keep coming back to that bullet for an elk load in my 30-06 (would opt for the 165 in a 308).
But there's still plenty to think about. Maybe I'll play with the 168 TTSX again. Or maybe I'll see if my rifle likes the 175 LRX. Or maybe I'll keep taking the Accubonds and just be a little extra mindful of the shot angle. As you put it, food for thought.
