Targets that go BOOM right back at ya..... Shockwave exploding targets
The sign out in front of the gun shop said 'Exploding targets'.
I remembered this after picking up the powder and bullets I originally stopped in for. Asking the sales clerk, he directed me to an end cap rack stocked with dozens of containers.
'Shockwave' exploding rifle targets, which are binary devices. The container is filled with a white granular substance resembling calcium chloride ice melter. As I understand it, it's ammonium nitrate, and when it's mixed with fine aluminum powder it becomes an explosive. Inside the container of white substance is a double bagged envelope of the aluminum powder. Following instructions, the two materials are combined in the container, and then gently mixed by rolling the container back and forth till it's all a uniform grey. That's it..... it has now changed from common garden fertilizer into an impact sensitive explosive.
What kind of impact? Well, that's the question then, isn't it? The instructions (and the store clerk) say it takes at least a .223 to detonate the container of explosive. The Shockwave company website says the same thing, and adds that a projectile velocity of at least 2200fps is required.
2200 fps? Why.... .223 is not the only cartridge that steps along above that speed. There are many. Most larger.... and some smaller. Say, the .17 hmr for instance.
Knowing that the one pound container, while exciting to detonate as a target, might be just a tad ..um... 'large' to use in my backyard, I had two questions in mind as I bought it. 1) Will it work in smaller amounts? 2) Will it detonate with a nice quiet .17 hmr?
See, I like most of my neighbors. With few exceptions, we get along very well indeed. Out of respect for them I like to keep my back yard shenanigans to a restrained minimum. I try to avoid earth shattering KABOOMS. Small understated kabooms... that's another story.
Mixing the binary explosive as directed, I used it to fill small jewelry type cardboard boxes. Taping the lids on with bright pink duct tape, a few of the neighbor boys and I moved to the backyard for some testing. Very, very happy neighbor boys, I might add.
What we found is this..... The .17 hmr will detonate a small box of the material just fine about 80% of the time at 50 yards. At 20 yards, it works 100% of the time. The boxes mostly just vanish. There is little clean up.
How loud is it, when using the small box as a container? Roughly equivalent to firing a big bore pistol... say a .44 magnum.
Safety wise, I would advise staying at that fifty yard distance. Eye and ear protection should go without saying. Also, do NOT transport the mixed material. Combine it on site and make your targets up right where you intend to shoot them. Should there be any of the mixed binary explosive left over, simply wing it across the yard. It will be a very green patch of grass come Spring.