Friday, May 04, 2007

Corbon Ammunition - 45 acp Caliber

Corbon .45 ACP "Compact Gun Load"

160-gr. DPX

By Stephen Camp

Corbon ammunition frequently offers the highest velocities for a given caliber and bullet weight of any commercial ammunition on the market. It comes as no surprise that most of it is rated +P. Rapidly expanding bullets, often with fragmentation, have been seen more often than not in ballistic gelatin blocks smacked by their ammunition.

Much of their line utilizes the aggressively expanding Sierra PJHP (Power Jacket Hollow Point), but in more recent times the company has developed a new line of personal protection ammunition. It is designated "DPX" for Deep Penetrating X-bullet and uses a homogenous copper alloy hollow point made by Barnes. The Barnes X-bullet has been long known to rifle hunters, but has not been used as much in the handgun community until more recent times.

Corbon offers DPX ammo in several calibers including 9mm, .38 Special, and .45 ACP.

This article will focus on a new load developed especially for the short-barrel .45 ACP handguns that continue to gain popularity. In fact, the box designates this load "Compact Gun Load". It should also be noted that unlike the majority of their ammo line, this is a standard pressure load.

Bullet weight is given as 160 grains and the listed velocity is 1050 ft/sec.

The Corbon 160-gr. standard pressure load uses a Barnes X-bullet, Remington case and a sufficient dollop of powder to develop a nominal muzzle velocity of 1050 ft/sec from a compact gun having a short barrel. The bullet is homogeneous and features a massive hollow point that measures 0.23" wide and 0.26" deep. This one weighed 160.2 grains. LOA for the loaded cartridge measured 1.25" with very little variation. On the picture at the top left, the groove in the bullet where the case is tightly taper-crimped is visible. Bullet setback is not expected to be a problem with this ammunition.

From what I've seen and read, this bullet will normally penetrate between about 12 and 13" in 10% ballistic gelatin and the buzzword seems to "consistent." Researchers advised that the bullet expands monotonously regardless of what barriers the bullet passes through before striking the gelatin. This includes the dreaded 4-layers of denim that often causes otherwise praised bullets to act like solids.

I do not have access to a controlled temperature environment where calibrated 10% gelatin can be used to the protocols of those following what is called the "scientific method" of testing. Nor have I had the opportunity to shoot anything living with this ammunition. As more and more of this ammunition is used and evaluated, I'm sure that the gelatin data will begin pouring in from various sources. I hope to try this on varmints in the field as well, but for this article informal expansion testing was done by firing into water.

The ammunition was tested for function, accuracy and expansion from three different handguns having three different barrel lengths.

Firearms Used: For this report, a Colt Defender, Commander and Dan Wesson Patriot were used to see how the Corbon 160-gr. DPX would feed, group and expand. The Defender is the compact of the bunch and the genre of pistol for which this ammunition is tailored. It has a 3" barrel compared to the Commander's 4.25" and the full-size Patriot's 5" tube. Each of these pistols is using its original factory barrel.

These three pistols were used with the "Compact Gun Load" from Corbon. I wanted to see the velocity differences as well as if the bullet would perform as well at the higher speeds than those from the 3" barrel.

Expansion was virtually identical regardless of which gun the ammunition was fired from.

Shooting: Though three guns were available, the bulk of today's shooting was done with the Colt Defender since it represents the launching platform Corbon's people envisioned this load for. The ammunition was fired at one distance, 15 yards. This was done from a seated position and using two hands in slow-fire. Some will argue that this is irrelevant in defensive ammo. I disagree. I want ammunition at least sufficiently accurate to allow for a precise shot at greater than arm's length should the necessity arise. One's ability to use a handgun effectively is more a result of practice and skill than ammunition so no "practical" shooting was done with this load.

Chronograph data resulted from ten shots fired approximately ten feet from the chronograph screens and shots fired into water passed through the chronograph screens so that the muzzle velocity resulting in that individual bullet's expansion would be known. If some expanded and some didn't, it might be possible to see a lower velocity thresh hold. (I needn't have worried about it.)

Here we see a 160-gr. Corbon DPX bullet that was fired from a Colt Defender's 3" barrel. The recovered bullet's dimensions measured 0.81 x 0.79 x 0.67" tall. Surprisingly, the expanded bullet weighed 165.2 grains.

Chronograph Data for Corbon 160-gr. DPX

Gun/bbl length (in.)

Average Velocity (ft/sec)

Extreme Spread (ft/sec)

Std. Deviation (ft/sec)









DW Patriot/5




With all three firearms, the average measured velocity exceeded that listed on the box. Extreme spreads were not excessive and the ammunition's consistency should not be a topic for concern.

This cartridge was fired in the Dan Wesson Patriot. The primer's visual appearance is that of standard pressure ammunition. Edges of the primer are still rounded and there is no evidence of even the beginning of a pierced primer. (Note that the primer is sealed.)

This slow-fired group was shot at 15 yards from a seated position and using a rest. It consists of five shots. The POA was the center of the dark bullseye

This 5-shot group using the Commander was fired in the same manner as the Defender and with the same POA.

The ammunition grouped very well from the 5" DW Patriot as it did from the Defender and Commander. The center of the bullseye was also the POA for this group as well. The Commander and Patriot are both sighted in for 230-gr. ammunition at 15 and 25 yards, respectively.

Observations: Though only 100 rounds total were fired, there were no failures of any kind in any of the test pistols. The bulk of the remaining ammo after the chronograph work and expansion testing were done was fired through the Defender. I failed to note the exact round count, but estimate it at roughly double that of the other two guns. Despite the somewhat sharp edges of around the hollow cavity, no gouges were noticed on either of the lightweight pistols having aluminum frames and two-piece feed ramps. When chamber rounds by hand from full magazines, no hesitation to feed was experienced, but this can be as much a function of the magazine as the bullet's ogive or the cartridge LOA. The Defender was used with a Wilson magazine, the Commander with an old Randall, and the Patriot with a McCormick PowerMag.

Ejection was consistent and felt recoil seemed quite similar to standard velocity 230-gr. ammunition, regardless of which pistol was being fired. Obviously, there will be more felt recoil with the 22.5-oz. Defender than the all-steel 5" Patriot, but felt recoil for that pistol felt about like hardball from the same gun. After writing the above, I cranked in the average velocities for the 160-gr. bullets at their average speeds and compared them to 230-gr. at the more or less typical 830 ft/sec.

From the Defender, the figures show that the recoil is approximately 91% of that received from 230-grs @ 830 ft/sec. The Commander was closest at 99% while the Patriot had 2% more than this average ball round.

I then compared these figures to the average velocities for 230-gr. ammunition fired from these specific pistols to compare with the 160-gr. momentum.

From the Colt Defender, Sellier & Bellot 230-gr. FMJ averages 722 ft/sec. Plugging in the numbers and turning the crank yields that the "Compact Gun Load" produces approximately 4% more "kick." The Commander averaged 781 ft/sec with the S&B. With the DPX, there's 13% more felt recoil. The DW Patriot consistently averages 799 ft/sec with the ball load. Using the DPX, felt recoil is 17% greater.

Looking for a common 230-gr. defensive load that I'd chronographed through all three pistols resulted in the following percentages.

Using Winchester 230-gr. "Subsonic" JHP, the Defender averages 774 ft/sec. Thus, the DPX load generates 3% more felt recoil…at least on paper. With the Commander, the 230-gr. JHP did 804 ft/sec. The DPX generates 98% of the 230-gr. ball round's momentum. From the 5" Patriot, Winchester 230-gr. Subsonic averages 889 ft/sec and the 160-gr. DPX produces about 5% less felt recoil.

Frankly, I couldn't tell the difference in actual firing, but perhaps these figures will help readers get an idea of what the load feels like. Keep in mind that felt recoil is very subjective, but this is as close as I can describe it. In no case did I find it either "sharp" or "excessive", just "typical" for the 45-caliber pistol being fired.

Based on my admittedly limited tests, I think that Corbon has a useful load here. The ammunition functioned fine in three different pistols using 3 different makes of magazines and grouped very well. It is a "light" bullet for caliber and this will turn some off from the start, but it may just be what the doctor ordered for people using the compact 45 autos and wanting muzzle velocities better than roughly 800 ft/sec with the traditional weight bullet. Fired from the longer barrels, the bullets did not fragment or fail to expand. I think that the only thing the additional velocity provides is more penetration. From the 3" barrel, this round is designed to meet today's accepted penetration levels. From the longer barrels, it would probably exceed it. The length of the "petals" limits expanded diameter and this has reportedly been incorporated into the bullet's construction.

If you are interested in a fast-stepping expanding bullet for your pocket .45 and prefer standard pressure, you might take a look at this cartridge. If you can control "hardball" in the small guns, I honestly think you will be able to do the same with this.

I've been very favorably impressed with other Corbon ammunition in the DPX line. I'm favorably impressed with this one too.

For those interested, here are some links for articles on other DPX ammunition:

Pricing and other information concerning Corbon's line of ammunition can be found at: