.25 NAA

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).

Performance
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.