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Bullet Jacket/Core Separation (03-23-12)
Roughly 25 years ago I was at the Reno SCI convention and happened to be in the Speer booth, when a very upset hunter stopped by to complain about Speer’s “horrible” .375 diameter, 285gr. Grand Slam bullet. As the story went, said hunter had just returned from Africa where he made a one shot kill on an enormous and beautiful 600 lb male lion. The man was furious with the Speer bullet engineers because when he autopsied his lion, he discovered that the bullet jacket had separated from the core and passed through the body cavity and stayed just under the off side skin of the lion, the jacket stayed inside the lion as well and made its own short path of destruction within the torso where it lodged.
In looking at the photos of this lion, I could not help but think how beautiful it was and how perfectly the bullet had performed for lion sized game, in spite of the fact that this guy was very upset. The Speer engineer listened and then very politely explained that the bullet had worked perfectly, which was demonstrated by the fact that the lion dropped on-the-spot. However, some place in the hunters mind was the fact (a non-fact) that no bullet should ever experience jacket/core separation, for any reason and that jacket/core separation was always a bad thing. Of course, this type of bullet performance would not give the penetration you’d want for shooting a 2,000 lb buffalo, but it was perfect for a 600 lb lion or 600 lb anything. In fact, bullet jacket/core separation and some fragmenting, is more deadly than a bullet that holds together, provided the fragmenting bullet still acquires enough penetration for the game being shot. Any time your bullet can make more than one terminal path of destruction, you simply get more destruction of organs, more bleeding and damage to the structural support system of the animal.
Another experience of roughly 25 years ago occurred on the North Fork of the John Day River in NE Oregon. I had back packed into wilderness several miles for a deer hunt, which turned into a black bear hunt after my deer tag was filled. As I picked my way along the north bank of the river, I spotted an averaged sized (around 200 lbs) black bear across the river, with a perfect deep black coat. I was using a 7MM Rem. Mag. rifle and a 140gr. Sierra bullet being launched at 3200+ fps. I knew this bullet would likely fragment on a close range target, (50 yards) which did not bother me because I had been hunting relatively thin bodied mule deer, that don’t require much penetration. The bear was standing broadside, so I made a perfect broadside double-lung shot. The bear ran about 40 yards, like most lung shot bears do and collapsed. Upon examination, I discovered the expected normal single entry hole, but there were at least 6 small exit holes on the opposite side of his rib cage. There was nothing left resembling lungs inside the bear. The bullet construction was not designed for a nearly 3200 fps impact with flesh and bone and had broken up. However, it gave sufficient penetration and because it broke up, it did much more damage than a bullet that would have held together. Again, this is wonderful performance for a bullet being used on 200 lb animals, but would have been a disaster on an 800 lb bull elk with a hard angling shot, that requires three feet of penetration.
Humans are another medium/target where some bullet jacket/core separation and bullet fragmenting can be more deadly than a bullet that simply passed through, leaving only one path of destruction as opposed to several. Humans, being thin and frail do not require much more than 14 to 18 inches of penetration if hit from the worst angles and if hit straight on, require only about 9 or10 inches of penetration before your bullet will exit the other side.
For the first many years of production, Nolser made their Ballistic Tip rifle bullet very fragile and that bullet would often turn into a mini grenade inside an animal if that animal was hit at close enough distance for impact velocity to be high enough. Since that first decade or so of production, Nosler has sadly made their Ballistic Tip bullet much tougher and it will no longer “grenade” inside an animal as easily. I killed a number of big game animals with that old Ballistic Tip bullet and provided I took only good angle (broadside) shots, it was the deadliest bullet around for lung-type shots on elk and deer. Of course I had to be willing to give up the quartering angle shots on elk, when using that bullet., but since mule deer are much smaller than an elk and require much less penetration, I could take quartering shots on deer with that bullet.
Now, I need to make myself perfectly clear or someone somewhere will assert the human tendency to misconstrue……Ample penetration is required to effectively kill any mammal, period, but if you can get ample penetration with a fragmenting bullet, it will normally be more deadly than a bullet that holds together and makes only one path of destruction. Penetration is absolute king, but once sufficient penetration has been achieved, the results are more devastating with a bullet that fragments and if that bullet does not fragment, no worries, as it will still keep penetrating and doing the damage of a single wound channel. Of course if I am hunting buffalo or elephant, I want a bullet that has no chance of separation as those animals are simply too large and tough for any bullet fragmentation of any type to be acceptable. However, the entire purpose of this article is to point out that shooting deer, small black bear and any number of other mammals, including humans, is very different than shooting elephants, so what applies to elephants and buffalo, does not perfectly apply to smaller animals, across the board. Choose your bullet performance accordingly and don’t worry about jacket/core separation in situations where actually enhances bullet effectiveness.
For more information, see my article on “Bonded” Bullets-Dispelling the Myth.