"My question is, does the bullet achieve both, or is it an either/or situation?"

This technology allows the bullet maker to make a core that is much harder than lead and will penetrate much farther than lead. It also allows the bullet maker to make a core that is more frangible than a lead bullet. The control mechanism is the amount of binder used, and how much pressure is used to bond the core particles. For example, the S.E.A.L. teams use a 79 grain frangible bullet that will break up very quickly on a hard surface because they work taking down ships and oil rigs that have many vertical steel surfaces in the operating environment, and they have suffered richochet type injuries with M855 and other lead bullets. It is much safer for them to use the super frangible core. The interesting thing is that tungsten is much harder than lead, and denser than lead. This fact allows the tungsten to penetrate farther than lead and do more tissue damage even after it has begun to frange.


One bullet can not "Do it all". The nature of tungsten allows a wider performance envelope than lead, especially when dealing with glass, and hard surfaces less than 3 inches thick, like a 'shoulder bone'.


That is, do the bullets which are sufficiently dense to penetrate heavy bone, still do the "explosive" type of wound channel, or do they fully penetrate?

Yes, they do. Typically when I hit an Elk on the front shoulder, there is about a 1/2 inch round hole in front of the shoulder bone, and some major bone fragments blown off the back, or inside of the the shoulder. In this situation, the lungs are liquid goo, and the bullet has completely franged in the chest cavity and there is no exit wound. In a different situation, I double lunged a Moose from a broad side shot, and broke a rib going in with a small entrance wound, and left a volley ball sizd exit wound on the far side. In both cases the bullet franged, but at different depths. On the elk, the franging starts seriously about 4 inches inside, and on the moose, it began about 7 inches in.


Or, is it more or less a trial and error deal where you experiment until you find the perfect core compression that achieves the balance of penetration/explosiveness that you need for a particular situation?

That is exactly what it was. We started with tests on live pigs, and then went to neck shooting elk, and then full on shoulder shots of moose and large bears. Most recently the testing has been on African game with some very large calibers, but I am not involved in those tests, and they are ongoing. We did not just experiment with core compression, we also changed the size of the particles, and the ratio of powders. We even found a combo that would give you a 240 grain 30 cal. boatail that was the size of a 168 Sierra Matchking. This core was very dense, and way too hard for hunting, it acted like a pass through arrow with no broadhead. Small hole going in, and coming out. There was major testing done to find the right compression and density to achieve reliable penetration and frangiblilty at the right depth.