Thursday, March 7, 2013

Corbon 32 NAA Clear Gel Testing JHP and FMJ

A few weeks ago, I published a test on the new Hornady Critical Defense 32 NAA load.  You can check that test out HERE.  This is a second test of the 32 NAA cartridge with two loads from Corbon, who is the only other 32 NAA ammo maker.  The three loads from Hornady and Corbon cover all the conventional JHP and FMJ ammunition offerings in this caliber.

The 32 NAA is a bottle-necked pistol cartridge spawned from the 380 Auto.  A 32 NAA is formed by necking down a 380 auto brass case to accept a 32 caliber bullet.  The concept behind the cartridge is to put more powder behind a 32 caliber bullet than is possible with the 32 Auto cartridge. 32 NAA ammunition is still very much a niche item with a very limited number of pistols available in the caliber and only two ammunition manufacturers producing loads in 32 NAA.

Test Pistol Specs:
Diamondback DB380MS with 2.8" 32 NAA Barrel

Testing Protocol:
My testing process is pretty simple.  I take one shot at the end of a Clear Ballistics Gel block that measures approximately 6" x 6" x 16" and weighs approximately 16 lbs.  I take the test shot from 8 feet away and impact velocity is measured less than 2 inches away from the block.  Clear Ballistics Gel is calibrated to 10% ballistics gel density.  I shoot the block at the range and then bring it home to analyze the block and recover the bullet.  Immediately prior to shooting the block, I take a 5 shot velocity test over a ProChrono Digital chronograph.

Test Results:
The test results are summarized in the data sheets below along with a close up shot of the recovered bullet.

Video documentation of the entire tests from range through bullet recovery are available below.  The high definition video is best viewed on YouTube, but you can also view it here.

My Thoughts on These Loads:

I've found that Corbon is usually pretty accurate with the muzzle velocity estimates printed on their packaging.  If they are on the high side with their estimates, it's usually off by less than 100 fps.  The FMJ had no problem averaging very close to the 1000 fps shown on the box.  The JHP tested about 80 fps slower than the published velocity. 

You probably noticed I have 3 recovered JHP bullets in the data sheet picture.  The first two shots skipped out of the block after approximately 10.5 inches.  This was poor shot placement on my part, but we did recover both bullets.  The third shot was captured in the block so it was weighed and measured.  All three recovered bullets show a very uniform expansion with the recovered round expanding close to 125% of original diameter.

Weight Retention:
As we saw in the review of the gel block, the JHP bullet is prone to minor fragmentation.  The recovered round still retained 97.5% of its starting weight.  Looking at the recovered bullet, it looks very much like a Hornady product.  I had some Hornady Custom .32 Auto XTP rounds in the ammo cabinet so I compared the bullets and they are slightly different in appearance.  I can say with certainty that this is not the same bullet that Corbon loads in their old or new 32 Auto JHP, which was tested HERE.  

The penetration of the JHP was really quite good for a tiny 60 grain bullet.  It easily beat the penetration performance seen with many 32 Auto and 380 Auto JHP loads.

I was hoping we would catch the FMJ test shot, but it managed to squeeze out of the bottom of the block after 15 inches of penetration.  Failure to recover is a huge disappointment for me when it occasionally happens.  
The calculated energy of the two test shots mirror the results we saw in the velocity testing.  The 71 FMJ was very close to published energy because it was very close to published velocity.  The 60 grain JHP was well short of the published energy value due to observed velocity well under that published on the box.

Wrap Up:
These two loads from Corbon tested well in my opinion.  The FMJ load delivered on velocity and demonstrated penetration that should appeal to all that value shot placement and penetration over an expanding round that doesn't penetrate at least 12 inches.  The JHP load ran slow from the test barrel and fell short of the 12 inch penetration that many feel to be a minimum requirement.  I have little doubt that we would have seen 12+ inches of penetration if we had achieved velocity of 1200 fps.

It will be interesting to see how the end consumer responds to the 32 NAA in the years to come.  Will it catch on as a lower recoil alternative to 380 Auto, or as a higher performance 32 Auto, or will it eventually fade into obscurity? 

Disclaimer....This test should not be considered an endorsement or recommendation for the product(s) tested.  All tests represent actual performance in ballistics testing media.  Terminal performance in all other media will show different results.  It is up to each individual to make their own personal decision on which specific ammunition to use for their needs.  It's also critically important to test any ammo in YOUR SPECIFIC FIREARM before relying on it for any purpose.

Ammunition labeled as +P or +P+ should only be used in firearms that have been certified by the manufacturer as safe for the additional pressures generated by these ammunition types.


  1. Thanks for doing this test and the previous one on the new Hornady load. The .32 NAA has always interested me, but it has never really seemed to catch on. I was curious when I saw Diamondback started selling the .32 barrels. Then when I saw Hornady come out with the 32 NAA in the Critical Defense line, I started wondering if there were more 32 NAA shooters out there than I had realized. Anyway, thanks for the good evaluation.

  2. Another facinating test. I think the. 32 NAA would see mor use if drop-in bsrrels were offered for some of the popular .380 pistols for which new replacement barrels are virtually impossible to find. In particular I would like to try this round in Colt 1908 Pocket Hammerless, whose original barrel is is pitted and washed out amost beyond use. Another candidate is the M1934 Beretta, which was a common WW2 bringback.

    The .32 NAA fired in your short-barrel test gun closely matches the velocity expected, firing RWS, Geco or Syntox 73-grain FMJ from my Walther PP with 3.9" barrel. A useful improvement.