I'm a total noob, so I apologize if you have answered this question before. At what depth of penetration in your test medium did you consider enough?
No apologies needed at all. In fact, it is an excellent question. It was the same question I had when I first started testing bullets some 30 years ago.
Let me define the medium and tell you why I decided to use the medium that I use.
In the very early years of test work I used straight wet news print. Medium has to be aqueous, animal tissue is aqueous, animals are not made of wood or dry material. To have any sort of simulation the medium has to be aqueous or you are testing something else.
At some point in the early days every day I would get the mail, there were 3-4 inches of catalogs that came to my wife! Its like we were being over run with these things, and I decided to see if I could incorporate some of these in the test work. It was a fluke, but what I learned is that if I used 2 inches of this catalog mix every 10 inches of total medium, it made a very dense, very tough medium on all bullets. Far tougher and more dense than animal tissue. Mind you, this medium was very well soaked, sometimes for days. I believe the introduction of these magazines/catalogs made the overall mix somewhere around 30% tougher/denser than straight wet print.
Now, the point is to STRESS the bullet, so you don't want to be EASY on it, you want to give it a hard test, a test that will show any short comings of design. But also not something that is not realistic, and something that can be repeated over years of different tests for real comparisons between designs.
We moved into our Indoor Facility about 20 years ago. Top of mind was doing bullet research so the back of the range was designed to do this, with drains in the floor for water to exit as the boxes were soaked daily. The first box built was held 65 inches of test medium. After we started testing some of the #13s and a few other designs, I found I needed a second box to catch some of these bullets, I had a few exit 65 inches.....
We had tested a lot of Round Nose Solids.......... RN are not stable during terminals....... I had a joke about setting up the boxes to test RN.......
We also used what I refer to as "Witness Cards", I took card stock paper, laminated it, and would insert into the mix at regular intervals to assist in showing me what was happening with a bullet at each depth. With trauma bullets cards were closer together. With Solids I would insert every 10 inches. These were measured extremely carefully so that each card was placed exactly the same all the way through the test medium. When you tested a Solid, you were then able to pull each Witness Card and tell exactly if you had straight line penetration all the way through, or if the bullet tended to veer off course, even slightly............
I think this is an example used for a trauma inflicting bullet...........
What all the test work did for us is show us bullet behavior in aqueous medium, potential failures and successes of different designs with both Solids and Trauma Inflicting bullets, and it showed us exactly how a particular bullet behaved, and how different design changes effected Terminal Performance.
Once proven in the test work, it was time to take it to the field. While we gained incredible knowledge in the test work, we learned even more in the field. Animal tissue and tested not only confirmed the test work, but showed us even more of how the bullet actually worked. It was an incredible journey.
Now, back to the Question at hand.......
At what depth of penetration in your test medium did you consider enough?
Years of digging bullets from animal tissue, solids, conventional softs, Generation 1 and Generation 2 CNC Trauma inflicting bullets, we began to put together a "Rule of Thumb" for each of these. Rule of Thumb is not absolute by any means, there are many factors that you will encounter in the field that cannot be duplicated with certainty on the range or in test work. Just one example, Bone!
With this in mind my Rule of Thumb for
Conventional Expanding Bullets is 70% more penetration in Animal Tissue than the Test Medium I use.
Gen 1 and Gen 2 CNC Trauma Inflicting bullets 100% more penetration in animal tissue than in the test medium.
SOLIDS 35% more penetration in animal tissue than in the test medium.
So the question is, How Much Penetration is needed in Animal Tissue?
How many inches is a buffalo broadside? Elephant Broadside? Hippo?
How about if you need a Solid from the rear to reach vitals of a fleeing buffalo? Elephant?
Frontal or side brain shots on elephant?
I won't tolerate Solids that do not drive dead straight. Only dead straight will give you reliable penetration and stability to accomplish the mission. Most proper designed big bore solids meant for serious work, elephant, buffalo, hippo, will drive 55-65 inches in the test medium dead straight.
This gives us Rule of Thumb 7-8 feet of penetration in animal tissue. And a pretty solid chance that we can get to the vitals even from some rear shots. Definitely on buffalo, carefully on elephant. I have had some of my .500 caliber rifles end to end elephant and exit. That is most comforting to know, in those worst case scenarios. In many cases to be quite honest, I also think my 35% for Solids is conservative for some designs.
In the example of some Lever Gun Solids, in particular the #13 CEB Design, they test at 40-45 inches. And this puts them at 5-6 feet of animal penetration, and that is nearly spot on from what I have seen on hippo and buffalo. But lets say elephant was on the menu, 5-6 feet, I would be very cautious about a rear end shot, I would take it if I had to, but it would be in the back of my mind. Broadside heart? No issue at all.
So such a complicated answer, for such a simple question....... But a much needed base of knowledge to work with. An excellent question.
Simple answer from me and for me............. How much is Enough? I always wish for more than enough!
