I did some bullet testing a few weeks ago, which I will summarize here, and I welcome any comments you may have.
I was testing bonded .35 calibre bullets in a wet phone book medium. My bullet weights were 200, 220 and 245 grains. My set-up was very poor, and I wasn’t able to fire as many shots as I’d hoped. My rifles were a .35 Remington, a .358 Winchester, a .35 Whelen and a .358 Norma.
First, a little background would be in order. I am not a fan of narrow wound channels, retained weight or exit wounds. I believe that the perfect bullet would provide some initial shock to the animal to stun it or put it down. The bullet would then resist expansion long enough to penetrate into the internal organs where it would rapidly expand and then fragment causing maximum tissue damage to the internal organs.
My bullet design incorporates a hollow tip made from an inverted jacket that is covering a small core inserted into the bullet’s primary (bonded) core. I’m using .030 main jackets and .015 tips. The intention is for the tip to collapse on impact causing the bullet tip to open a certain amount to provide the initial shock. The remnant tip, the small core and the bonded major core would then act to temporarily impede expansion while the bullet penetrates the body wall and possibly bone. The bullet would then expand rapidly and then fragment, causing maximum internal damage. I’ve shot two deer with non-bonded versions of this bullet, and in both cases, the animals dropped like rocks with their lungs shredded, and there were one-inch exit wounds (not expected). :shock:
In every case, during my recent testing, there were indications of impact shock from the collapsing tip, with cratering at the point of impact. Several of my tests, however, resulted in the bullet tumbling shortly after impact. :? This seemed to happen only with the Remington and Winchester rounds, and at lower velocities. I believe that this was the result of the violence of the initial impact and collapse of the tip. It seems that the lower velocity rounds weren’t able to overcome the initial upset. The higher velocity loads seemed to maintain their stability inside the expansion medium. I have been shooting these bullets at paper for a few years, and have never had any indication of key-holing, so the upset had to happen after impact.
A bullet that tumbles inside the animal isn’t necessarily a bad thing – after-all, that’s one of the things that initially sold the M16 to the US military. It’s simply unexpected and not what I anticipated. The wound channels were 2 to 3 inches for most of their length, and quite deep averaging about 19 inches.
Otherwise, the wound channels seemed to be about what I expected. For example, my 245 grain bonded at 2825 fps gradually expanded to about one inch at a depth of 4 ½ inches, and then went quite rapidly to 4 inches in diameter at 6” of penetration. It then held an average diameter of 6 inches for the next half-foot of penetration. The wound channel then declined quite rapidly to where the bullet fragments stopped at 16“ from the point of impact.
I encountered one other thing that concerned me. In two cases, when I picked up the base of the bullet with a lead remnant in it, I was able to separate the lead from the jacket with the force of my thumb. :shock: This indicates that the base wasn’t bonded, however, other bullet fragments (from the walls of the same bullets) still had lead bonded to the copper jacket. It’s my assumption that the “core bond” flux wasn’t present at the base of the bullet when I melted the core inside the jacket with my propane torch.
I’ve been using the method recommended by Corbin of inserting the core into the jacket, then putting a couple of drops of flux in on top of the core. For a while I tried putting one drop of flux in first, but I found a couple of cores shooting out of the jackets :oops: propelled by boiling flux, so I discontinued the practice. Has anyone else been faced with this problem? I’m thinking of going back and trying the “drop-in-first” method again. Maybe it’s common for the bond to break down at the base of the bullet?
Thanks!