Polycase ARX Inceptor

This is a guest post by Andrew Betts

The oddly named Polycase ARX Inceptor does not have a polymer case. It has a brass case and the projectile is composed of injection molded polymer and powdered metal. The manufacturer says that it can produce wounds like those seen from rifles and manufacturers never exaggerate their claims, right? I mean, the folks who make the product ought to know the most about how it works and what incentive to they have to exaggerate its effectiveness?

That really does seem to be a quite literally fantastic claim, though. On the surface, it seems reasonable because they have some legitimate sounding explanations about the rotational forces, fluid dynamics, and flux capacitors. It sounds suspicious that a pistol round could produce as much damage as a rifle round, though. As Robert A. Heinlein said, “There ain’t no such thing as a free lunch,” and this claim seems to expect something for nothing. Is it really possible?

If we examine the performance of these projectiles in ballistic gelatin, we find that they do, indeed, create a substantial wound channel. Despite being unable to expand, they produce significant disruption and a large temporary cavity, beginning early in the “wound” track and continuing for a good six inches or so.

The first thing that stands out is that the extent of this damage, while impressive, is not actually consistent with a rifle wound, as the manufacturer claims. Even at a simulated 475 yards, this .223 round produces substantially more damage than seen from the ARX round.

There is an obvious and dramatic difference between those two rounds. There is simply no comparison. In this regard, the manufacturer’s claim is gross exaggeration at best. That said, the wound track does seem to be larger than what we would expect to see from any non-expanding bullet and even looks larger than is typical for modern, premium JHP defensive loads. How can this be?

The short answer is that the high velocity causes a larger temporary stretch cavity. The key here, though, is that word “temporary”. When a bullet passes through tissue, its passage crushes, tears, and removes some tissue. This is called the permanent cavity. Some tissue is also accelerated away from the bullet laterally, this causes a temporary cavity. Tissue moves aside, then returns to place.

Gelatin is not nearly as elastic as real tissue so it tears much more easily, creating the illusion of damage, whereas real tissues might have simply snapped back into place with nothing more than bruising. If the projectile is moving fast enough, the tissue that is pushed to the side is pushed farther apart and can exceed the elastic limit of the tissue, at which point, the tissue tears. This threshold is approximately 2,000 fps.

That means that the “damage” that we are seeing from the ARX is not really damage at all. At least, it does not compare readily with the damage that would be seen in real tissue. This means that the manufacturers’ claims are false in every regard. This should come as no surprise, though. There are two strong warning signs here that should make you strongly skeptical even if you did not see the testing and did not know the physics. The first is that the manufacturer is claiming to have discovered a principle that no one else knows. This is certainly possible, of course, but highly unlikely.

Man has been using firearms since 1634. While there are regular, incremental advances, foundational shifts such as Polycase is claiming are rare. It stands to reason that if their claims were accurate, someone else would have discovered the principle at some point in the intervening 381 years. The second serious warning sign is that the manufacturer is claiming to be able to avoid making the necessary compromises that every other ammunition maker is forced to concede. They are claiming to have adequate (but not excessive) penetration and good tissue damage. As the saying goes, if something seems too good to be true, it probably is.

Andrew Betts served with the Arizona National Guard for over 12 years, including a tour to Afghanistan. Visit his YouTube Channel for more great shooting information.

Photo credit – Andrew Betts