A while back BBTI got ahold of me and said they had some Underwood ammo left over from their testing. Would I like to do some tests myself? Yes, yes I would thank you! What they very graciously sent me was two boxes each of 9mm Xtreme Defender and 9mm Hero ammunition. Both bullets are light-for-caliber at 65 and 70 grains respectively, and I was eager to try them out.

Light-for-caliber bullets propelled to extreme velocities is an idea that just will not go away. The idea has always been that a light bullet moving very quickly has a lot of energy, and that it will dump that energy rapidly. The thought was that this would cause a physical shock that would incapacitate the target. In reality there just isn’t enough energy there to cause that kind of shock, so the bullet simply under-penetrates badly enough that it can’t reliably reach vital structures. Unless it doesn’t expand, in which case the permanent wound cavity is quite small.

Energy is great, but momentum is your friend when it comes to penetration. Light-for-caliber bullets lack sectional density, which is the ratio of mass to cross section, and penetration is greatly enhanced by having a high sectional density. This is why tanks shoot long, narrow, heavy darts at each other these days. Because physics.

For my test gun I used my Sig-Sauer P6. This has a 3-3/4″ barrel, comparable to many mid-size EDC-style guns. Both of these bullets claim very high velocity for a 9mm, but are not +P rated. I expected that with the shorter barrel velocities would be below the claimed velocity for these cartridges, and I wasn’t wrong. I set up the Caldwell chronograph in front of blocks of Clear Ballistics 10% ordinance gel covered with four layers of denim. All shots were fired from approximately ten feet. Let’s start with the Heros.

Hero or Zero?

I confess to some doubts about this one. In previous tests light-for-caliber hollow-points usually exhibit spectacular expansion and poor penetration and, spoilers, these were no exception.

Claimed velocity is 1650 fps., which with the 70gr. bullet would yield 423 ft./lbs. of energy. From the P6 they averaged 1569 fps. for 383 ft./lbs. Not bad, and given the shorter barrel of this gun not wildly off.

Bullets expanded to an average of .68 caliber. Impressive!

Rather less impressive was their penetration. The two bullets fired into the gel both penetrated damn near exactly 9 1/2″. In fact bullets fired into bare gel also penetrated about 9-1/2″. Gold Star for consistency, then.

The Permanent Wound Cavity is reasonably impressive, with the bullets expanding immediately and creating a zone of significant disruption about 5″ long, and never fully streamlining. In the track above the bullet came to rest at 90 degrees from the direction of travel.

The FBI specifies a minimum of 12″ of penetration when fired into 10% ordinance gel through four layers of 16oz. denim, and this falls significantly short of that. I consider this a dubious choice for self-defense and would never recommend it for duty ammo. That being said I bet it’s awesome on pests and varmints!

Seriously, what do people have against ‘E’s?

Next came the Xtreme Defender ammunition. These also use a monolithic copper bullet, but they are about as different from a hollow-point as you can imagine. The bullet itself is produced by Lehigh Defense, who makes special purpose ammunition for the armed forces among other things.

The point has been described as being like a flattened Phillips screwdriver tip. The theory is the ogives cut into the bullet combine with the bullet’s rotation to displace tissue. It’s claimed that this produces a hollow-point-like permanent wound cavity, but is barrier-blind to clothing, windows etc. which can seriously affect the performance of conventional ammunition.

The claimed velocity for these bullets is 1700 fps., which produces 417 ft./lbs. of energy. The result I got was an average of 1660 fps. for 398 ft./lbs. Again, given the shorter barrel this isn’t far off at all.

Under-penetration was not an issue for these bullets. The sample went 16″ and was found on the table between the blocks of ballistic gel. It was difficult to get a good photo of this PWC; after several re-castings the Clear Ballistics gel as become Not Very Clear Ballistics gel.

The damage in the gel is very comparable to hollow-point ammunition. You can see the spiral created by the ogives as the bullet rotated. The bullet maintained a zone of disruption right up to about nine or ten inches, where it appears to have tumbled, then streamlined for the last three or so inches before it exited the gel. The wound track crosses the block at an angle because of me, not because the wound channel curves.

This bullet appears to have the chops for a self-defense round. Penetration is good but not excessive, and the Permanent Wound Cavity looks good. BUT… This is gel, not flesh, and gel is a comparative media, not a predictive one. Bullets that perform in gel usually, but do not always, perform well in flesh-and-bone targets.

If you want to carry these for self-defense or as a duty round I wouldn’t think you were nuts. All the indications are good and they don’t have excessive penetration, unlike ball ammunition. Plus they perform well against heavy clothing and barriers. In other tests I have seen they maintain an acceptable level of performance even after penetrating windshields, drywall and sheet metal. Personally I’m going to reserve judgement on this one.

The Takeaway

So, two LFC monolithic copper bullets, two different wounding mechanisms, both driven to extreme velocities for their cartridge. The ultra-light hollow-point works like they do; spectacular expansion, poor penetration. Works well against smallish critters, not so much on humans. The other…

Hell, we don’t even have a name for this type of bullet. It’s a very different idea, and it appears to work. It seems to have some advantages over conventional self-defense bullets as well, especially for law enforcement duty. The question is do these qualities carry over into the real world? Time will tell, I suppose.

So, for civilian self-defense and duty the Hero gets a big No. The Xtreme Defender gets a tentative yes; apparently it will at least not work worse than ball, and might work a hell of a lot better. I want more real-world data before firming up that yes.

Shout out to my supporters at Patreon for supplying the Clear Ballistics gel that will replace this murky stuff!

Take care and stay safe.

Michael Tinker Pearce, 10 June 2021

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