Tag: penetration

January 25, 2024 – Practical Performance

January 25, 2024 /

I have wanted not just make energy measurements but also to see practical performance this year. This means that I need targets that represents practical or real life situations. Many years ago, I occasionally liked to visit a site called The Box O Truth which seems to be a forum these days. It started out as a guy that would build targets and test different loads against them.

I decided to build my own Box of Truth. Not necessarily to duplicate what already has been done but to satisfy my own curiosity. I built what represents an interior partition wall to see if it will stop air rifle pellets. If not, is there a pellet weight or energy that will be stopped? This is a question of safety, what happens when a projectile hits an interior wall.

There are all kinds of variations that could be built. Instead of two sheets of drywall, I could add sheathing and siding representing an exterior wall. Since my pellet trap has a 3/4″ sheet of plywood for the back, I already know that it cannot penetrate that thickness. But, if I was testing firearms, that might be useful information. You could also build several of these things to represent the penetration of several rooms.

From top left to bottom right is Crossman Copperhead (3.5 ft/lbs), Crossman Piranha (11.6 ft/lbs), Gamo Blue Flame (16 ft/lbs) and H&N Slug HP (12 ft/lbs). The BB was from the Crossman Legacy 1000 at four pumps while the remaining pellets were from the Crossman Optimus. All three pellets penetrated the ‘wall’. The BB did not. I know that because I could feel them embedded in the first layer with no indication of back penetration.

What I have learned is that an errant shot or a deliberate shot into a partition wall offers no safety. While there is never an excuse for negligent discharge, it should give you pause for self defense and where your shots go including a single family dwelling or neighbors in a attached living scenario.

Nothing is ever perfect. This is a test that is basically two layers of drywall. There could be pipes, wires or structure in those walls causing unpredictable results but not in my case. In addition, I put insulation between the walls because I had it laying around from my duct work. Many partition walls have no insulation and there are different types of insulation densities as well. Each one the variables along with luck makes a difference. What is hard to measure is the exact energy or potential harm after the projectile goes through the wall. Just because it penetrates, doesn’t mean it is lethal but it is foolish to assume otherwise.

In the future, I would like to do some more deterministic testing. That means developing a target that shows how energy relates to depth of penetration. There are some homemade ballistic gelatin recipes and techniques that I am interested in investigating. But, I am not quite ready to do that yet.

End Your Programming Routine: Data really means nothing without correlation. Ten ft-lbs versus 20 ft-lbs has no context unless it can be applied to something meaningful. If 20 ft-lbs can go through 1/2″ plywood but 10 cannot, then you have information to be able to make decisions under those variables. My test really didn’t prove anything other than don’t shoot at your walls, but then you shouldn’t be doing that anyway. Really, the next logical step would be to find out how much energy would be required to penetrate both layers.

December 14, 2023 – And Now, Performance

December 14, 2023 /

I was looking through my stuff and I realized that I had six different cans of white spray paint. I don’t exactly know why that is the case but I was going to paint a project that I was working on white and I wanted to see what I had. As it turns out, three of those cans started spraying and then plugged up. I tried to clean them and figure out their day had passed.

I was going to throw them away, but I didn’t want to do so pressurized. I also didn’t want to poke a hole in them pressurize because that is a good way to have white paint sprayed everywhere. So, decided to shoot them with my pellet rifles. I thought I would use the same pellet in three different rifles to see the performance difference at three different power levels.

What I learned was actually not as much as I thought I would. All three rifles shot through both sides of each can. I have the energy calculations for each combo but when that exceeds the standard, it doesn’t tell much about performance. For a while now, I have been thinking about how I would test performance of these difference rifle/pellet combinations.

I have the pictures in order of power where the first one to the left is the lowest. One other thing you might observe is not every shot is dead center. This is because I don’t have every rifle sighted in for this pellet weight. But, I will say that this is an honest to goodness, three shots. There were no misses.

The first shot (left) was the most fun. When it hit, it twisted out of the box and sprayed paint all over the place. This is why the term reactive target exists. The target is hit and reacts. I thought that all three might do that, but that wasn’t the case. Since I have shot spray paint with 22lr before, I was kind of expecting it. This is why I had them inside a box to contain the mess.

I have heard from others that cans of shaving cream will do this as well. The advantage of those is the foam dissipates with the addition of rain. In my case, the small amount of paint on the grass will eventually get mowed and collected. But, if you are going to do something like this, be sure you have a good radius between your target and anything you wouldn’t want sprayed with paint.

End Your Programming Routine: I will continue to collect energy information and that is a good baseline to know. But I will also continue to look for a way to quantify what energy means against some sort of target. It appears that spray paint cans are not the answer, but I kind of wish that I had some more.