The extreme expansion capability of Corbon DPX ammunition is evident in this 9mm test bullet. Photo Dave Spaulding
This high-speed photo shows just how fast the Barnes X copper hollow-point bullet expands. Photo courtesy Corbon
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The debate over the incapacitation potential (i.e., stopping power) of various styles and calibers of ammunition will never end until we can all put our Star Trek phasers on stun. It s fine to argue calibers, bullet design, energy dump, penetration, bullet weight and velocity, and I will discuss some of this below. First, though, I must mention the one constant that cannot be disputed: You must hit what you are shooting at.
Equipment will never make up for lack of training a bullet s ability to incapacitate is a direct result of delivering a solid hit on the target. In addition, the more times you hit a given target, the more likely you will incapacitate it. As much as we may want to over-think this subject, the fact remains that incapacitating an adversary comes down to hitting that target solidly as often as possible. Once you understand this and undertake a training program to reflect this understanding, then and only then should you consider the type of ammo you load into the firearm. OK, on to the ammunition.
Small-arms ammo has changed little over the last half century. Following a devastating shootout involving a group of FBI agents and a pair of very committed armed robbers in Florida in 1986, a great deal of R&D went into ammunition design and development. While the ammo that resulted from this period was better than anything previously available, it was still basically a lead core surrounded by a soft metal jacket that was pre-stressed to assist deformation, or what many call expansion. It was also designed to hold the core and jacket together for greater hard-object as well as soft-tissue penetration. While this sounds good, designing a bullet that will hold together while it penetrates deeply but will also deform reliably is easier said than done. The major manufacturers of defensive ammo have done a darn good job of achieving this performance compromise.
The Corbon ammunition company has taken the next step in ammunition technology in the development of its Deep Penetrating X (DPX) bullet. Utilizing the proven Barnes X all-copper hollow-point bullet, Corbon has developed a high-velocity round that both penetrates and reliably deforms in a consistent manner. While the Barnes bullet is available in a wide range of calibers, Corbon s DPX ammunition is directed expressly at the law enforcement market in the most popular calibers of 9mm, .40, .357 SIG, .45, 5.56mm and .308.
Each Barnes X bullet is totally lead-free with a deep hollow-point cavity. Each bullet is scored so that it folds back into multiple petals. Remember, the Barnes bullet is not a copper jacket over lead. Because the bullet itself is copper, it can be designed to fold back with greater consistency than a traditional jacketed hollow point. Because the bullet is a solid component, fragmentation is all but eliminated, and the folded-back petals allow tissue to pass between them, giving the bullet deeper soft-tissue penetration. Additionally, the solid-copper bullet offers better hard-object penetration than a traditional lead-core bullet, which is more likely to break apart.
This type of hard-object penetration is important to law enforcement professionals because many confrontations occur in and around automobiles, businesses and residences. At the same time, over-penetration is also a concern because a bullet that passes through a justifiably shot suspect and strikes an innocent citizen will become a legal problem. I don t like to overemphasize liability because doing so endangers street cops by creating a potential for deadly hesitation. Still, it s not unreasonable to picture a miniature lawyer dressed in a pinstriped Brooks Brothers suit hanging from a rope attached to the tail end of an officer-fired bullet as it travels toward its target. Now that is a sight that will send a chill up your spine.
During a recent trip to the range, I performed a series of tests of the Corbon DPX load (see Range Tests ). First, I tested the load in the most popular police calibers. I used Glocks for my test guns and placed the tissue simulant 15 feet from the firing point.
I also tested Corbon s new 62-grain 5.56mm DPX load from a Stag Arms Model 3 with a 16" barrel. I placed the tissue simulant 25 yards from the firing point to get a better idea of how well it would perform at rifle distances.
While far from scientific, I decided I wanted to see how well the DPX would perform when fired through a common intermediate barrier. I chose the common car door in the shape of a 1998 Pontiac Grand Am. I opened the door and placed the tissue simulant two feet behind it. Then I marked the opposing side of the door to give a proper point of aim and to see how much deflection I d get.
I didn t weigh the bullets before firing them, but I think it s safe to say all of the DPX bullets retained 100 percent of their weight as they passed through the car door. While I m the first to admit my test was hastily put together and is by no means as comprehensive as a test performed in a ballistic laboratory, I was encouraged by what I saw.
Yes, the DPX is a bit more expensive than traditional lead bullets, and this will hurt Corbon in the very competitive government-bid process, but the advanced design and the complexity of the manufacturing process of the Barnes X bullet should be considered. Not all bullets are the same, and bid specifications should reflect this reality.
While actual shooting incidents with the DPX bullet remain very few in number due to its newness on the market, the few that have occurred reveal the DPX performs as intended. If your agency is in the process of evaluating ammunition for future adoption, the Corbon DPX deserves a close look.
Bullet Velocity Expansion Penetration
115-grain 9mm DPX 1,287 fps .66 inches 13.0 inches
140-grain .40 DPX 1,197 fps .69 inches 14.5 inches
185-grain .45 ACP +P 1,057 fps .72 inches 14.5 inches
Bullet Velocity Expansion Penetration
62-grain 5.56mm DPX 2,937 fps .50 inches 17 inches
Bullet Expansion Penetration Recovered Bullet Wt.
115-grain 9mm DPX .59 11.5 inches 114.5 grains
140-grain .40 DPX .59 12.75 inches 139.0 grains
185-grain .45 DPX +P .64 13.5 inches 185.0 grains
62-grain 5.56mm DPX .49 14.0 inches 61.5 grains
Corbon Glaser, LLC
1311 Industry Road
Sturgis, SD 57785