Ammo Test — The Curious Case of the 32 NAA Cartridge

32 caliber pistol and revolver cartridges are considered somewhat light for personal protection today, but despite the caliber’s waning industry support, such offerings have always had a strong undercurrent of fans. I contend that a good .32 revolver is a flexible option for anything from small-game handgun hunting to defense. Likewise, it is possible—albeit difficult—to get a compact .32 ACP pistol that is even more compact than the more popular and powerful 380 ACP. Between those two calibers, little is lost ballistically but with a .32, you have the potential for less recoil and a few extra rounds in your magazine.

The 32 NAA cartridge next to a conventional 380 ACP round.
The 32 NAA (left) is a .380 round (right) necked down to use .32 caliber projectiles at high velocities.

In 2002, North American Arms attempted to split the difference between these two cartridges when it introduced the .32 NAA chambered in their Guardian series of 32 ACP and 380 ACP pistols. The concept behind the .32 NAA is simple enough: take a larger .380 ACP case and neck it down to accept a .32 caliber (actually .313 inch diameter) bullet. The added powder capacity of using the larger case would theoretically allow greater velocity and better performance of smaller, lighter 32 caliber bullets on target. Additionally, it is a bottlenecked cartridge that may feed more reliably in small pistols than its straight-walled parent.

Twenty years after its introduction, the .32 NAA cartridge can best be described as a boutique round that never caught on. North American Arms still offers their Guardian in this cartridge and Diamondback offered a .32 NAA conversion barrel for their .380 pistol. But all mainstream manufacturers have all but given up loading for the round; among those was Hornady who offered a heavy-for-caliber 80-grain Critical Defense FTX loading.

The 32 NAA Load

The 32 NAA was generally offered using conventional 32 ACP projectiles from 71-grain full metal jacket loads to 60-grain hollow-points with advertised velocities ranging from 1000-1200 feet per second respectively. Out of a short 2.5-inch barreled Guardian, that sounds impressive. Even more so, considering that neither conventional 32 ACP nor 380 ACP ammunition approach those velocities. That 71-grain load could give impressive penetration but in conventional gelatin tests, the 32 NAA was simply too hot for hollow points designed around 32 ACP, with overzealous expansion and light penetration. The 80-grain bullet Hornady loaded was advertised at 1000 feet per second and its heavy-for-caliber red-plugged bonded hollow-point promised more controlled expansion with enough penetration to get the job done.

Testing 32 NAA

I shot a string of five rounds over my Caldwell Chronograph from ten feet away using a .32 NAA Guardian. With an average velocity of 982 feet per second, this load had a 100-200 feet per second premium over the 32 ACP and it was done with a heavier bullet. The cost came in recoil. Out of that little blowback pistol, I did not get the impression that those lighter pills translated to lower recoil than a conventional 380. Boasting 171 foot-pounds of muzzle energy, this 32 NAA load is certainly on par with a typical 380 on paper. So why bother with 32 NAA if it has the same recoil and power as a 380? The answer should lie in terminal performance.

The wound paths of three 32 NAA slugs in gelatin
The wound paths of three 32 NAA slugs in gelatin.

From the same distance, I fired four rounds through stacked 10% Clear Ballistics ordinance gelatin blocks shielded by four layers of denim. This is not a definitive ballistic test but a worst-case scenario that can be repeated for different loads. The 32 NAA underperformed but even in failure, there was plenty to appreciate.

Three rounds of 32 NAA suspended in gelatin.
Three rounds of 32 NAA, suspended in gelatin.

One round skimmed through my blocks at an angle and exited under my table—oops. But the last three connected, going through my denim barrier into gelatin blocks. The first round failed to expand and came to rest base first at the fourteen-inch mark. The other two projectiles also landed base first at the 9 3/4 and 11-inch marks. The latter projectiles expanded early on into the block before tumbling and coming to rest.

Their diameters, when pulled from the block and measured were .362 inch for the shallowest round, while the second opened zealously to .52 inch. The expansion was not consistent but tumbling certainly was. Both expanded rounds tumbled in “tissue.” The unexpanded projectile tumbled intact, leaving a large inch-wide tract between the six-to-eight-inch mark—not unlike how many unexpanded 380s behave.

The NAA Guardian in 32 NAA with fired and unfired rounds.
The NAA Guardian in 32 NAA with fired and unfired rounds.

Parting Shots

The 32 NAA is an honest concept, and Hornady’s 80-grain Critical Defense load was an honest attempt to improve on that concept. Original 60-grain loadings fell well short of the FBI’s 12-18 inch general rule on duty pistol performance in ballistic gel testing, but this heavier load cuts it close. While the 32 NAA was something of a failure in terms of sales, in this test, the load’s tumbling characteristics and higher velocity could be fully harnessed to surprising effect if paired with a good, nonexpanding full metal jacket loading. Loaders, are you listening?

Terril is an economic historian with a penchant for all things firearm related. Originally a pot hunter hailing from south Louisiana, he currently covers firearms and reloading topics in print and on his All Outdoors YouTube page. When he isn't delving into rimfire ballistics, pocket pistols, and colonial arms, Terril can be found perfecting his fire-starting techniques, photographing wildlife, and getting lost in the archives.

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