| File:Corbon .32 NAA JHP.jpgFile:Dpx32naa60.jpgFile:CORBON's .32 NAA 71gr Performance Match FMJ.jpg|
Various .32 NAA cartridges by Corbon.
|Place of origin||USA|
|Designer||North American Arms / Ed Sanow|
|Manufacturer||North American Arms|
|Parent case||.380 ACP|
|Case type||Rimless, bottlenecked|
|Bullet diameter||.3129 in (Script error mm)|
|Neck diameter||.3365 in (Script error mm)|
|Shoulder diameter||.3729 in (Script error mm)|
|Base diameter||.3740 in (Script error mm)|
|Rim diameter||.3740 in (Script error mm)|
|Rim thickness||.045 in (Script error mm)|
|Case length||.680 in (Script error mm)|
|Overall length||.984 in (Script error mm)|
|Case capacity||10.5 gr H2O (0.683 cm³)|
|Rifling twist||1 in 16 in (Script error mm)|
|Primer type||small pistol|
|Maximum pressure||25,700 psi (Script error MPa)|
|60 gr (Script error g) JHP||1,222 ft/s (Script error m/s)||199 ft·lbf (Script error J)|
|71 gr (Script error g) FMJ||1,000 ft/s (Script error m/s)||158 ft·lbf (Script error J)|
| Test barrel length: 2.5|
Source(s): Cartridges of the World 
The .32 NAA is a cartridge/firearm 'system' designed and developed by the partnership of North American Arms and Corbon Ammunition. The cartridge is a .380 ACP case necked-down to hold a .32 caliber bullet with the goal of improved ballistic performance over the .32 ACP.
History and DesignEdit
Bottleneck handgun cartridge designs experienced early success and have had continuing development since at least the 7.65x25mm Borchardt or earlier, which lead to the development of the 7.63x25 Mauser (also known as the .30 Mauser), followed by the 7.62x25 Tokarev. The benefits of bottleneck designs include smooth feeding and chambering and simple, robust headspacing.
The .32 NAA is the most recent of a line of commercial bottleneck handgun cartridges. Renewed western interest in bottleneck handgun cartridges began with the .357 SIG in 1994 (necking a .40 S&W case down to a .355 bullet); followed by the .400 Corbon in 1996 (necking a .45 ACP case down to hold a .40 cal. bullet); and then the .25 NAA in 1999 (necking a .32 ACP case down to hold a .25 cal. bullet).
The cartridge delivers in excess of 1,222 ft/s (Script error m/s) velocity to a 60 grain (3.9 gram) proprietary bullet from Hornady. This generates 199 ft·lbf (Script error J) of energy from the 2.5" Guardian barrel (1453 ft/s & 287 ft·lbf (Script error J) from a 4" test barrel).
According to Phil W. Johnston, the 60 gr Corbon cartridge averaged 1204 fps, with an extreme spread of 69 fps and a standard deviation of 19 fps, for 193.09 ft-lbs of energy. When fired at ballistic gelatin, he obtained 6.25" of penetration, with expansion to 0.528" and 72% weight retention.
The North American Arms Guardian 32 NAA is designed around this cartridge.
- ↑ Cartridges of the World 11th Edition, Book by Frank C. Barnes, Edited by Stan Skinner, Gun Digest Books, 2006, ISBN 0-89689-297-2 p.291
- ↑ North American Arms, 32 NAA Guardian, retrieved 2012 May 12
- ↑ Handguns, "The Mouse Gun That Roared," retrieved 2012 May 12
- ↑ Extreme Shock Ammunition, Enhanced Penetration Rounds, retrieved 2012 May 12
- ↑ Hornady Manufacturing, 32 NAA 80 gr FTX Critical Defense, retrieved 2012 Nov 23
- ↑ Diamondback Firearms, .32 NAA Conversion Barrel for DB380, retrieved 2012 May 12
- ↑ Makarov.com, The .32 NAA Conversion for the Makarov Pistol, retrieved 2012 May 12