|This article needs additional citations for verification. (January 2013)|
|Place of origin||United States|
|Manufacturer||North American Arms|
|Parent case||.32 ACP|
|Case type||Rimless, bottlenecked|
|Bullet diameter||.251 in (6.4 mm)|
|Neck diameter||.276 in (7.0 mm)|
|Shoulder diameter||.333 in (8.5 mm)|
|Base diameter||.337 in (8.6 mm)|
|Rim diameter||.337 in (8.6 mm)|
|Rim thickness||.046 in (1.2 mm)|
|Case length||.745 in (18.9 mm)|
|Overall length||.960 in (24.4 mm)|
|Case capacity||9.75 gr H2O (0.632 cm3)|
|Rifling twist||1 in 16 in (410 mm)|
|Primer type||Small Pistol|
|Maximum pressure||23,000 psi (160 MPa)|
|Source(s): Cartridges of the World|
The .25 NAA was introduced by North American Arms company for their smaller (height: 1/4" less; length: 1/3" less) and lighter (by approx. 25%) .32 ACP Guardian model. It is simply the .32 ACP necked down to accept .251" diameter (.25 ACP) bullets.
History and Design
The cartridge was originally conceived and prototyped by gunwriter J.B. Wood and called the 25/32 JBW. North American Arms and Cor-Bon Ammunition then further developed the cartridge and the NAA Guardian .25 NAA pistol combination for production in consultation with Ed Sanow. The finalized cartridge and pistol were introduced at the 2004 SHOT Show.
It followed the successful introduction of two other commercial bottleneck handgun cartridges, the .357 SIG in 1994 (which necked a .40 S&W case down to accept .355 cal. bullets); and the .400 Corbon in 1996 (which necked a .45 ACP case down to accept .40 cal. bullets).
According to NAA's website, the .25 NAA's 35 gr bullet travels faster (1200 f.p.s.) and hits harder (20% more energy on average) than larger, .32 ACP caliber bullets.
- "NAA Guardian Review". defensereview.com. Archived from the original on 27 September 2007.
- ".25 NAA Official Press Release". naaminis.com. Archived from the original on 22 July 2011.
- "Penetration test results". naaminis.com. Archived from the original on 22 July 2011. at NAA website
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