The .25 NAA (AKA: .25-32 JBW) is a Center Fire cartridge with a Bullet Diameter of 0.251 in” (6.38mm) that is primarily used in Pistols. The .25 NAA originated in The United States in 1999. The .25 NAA also has a case length of 0.745 in” (18.92mm) and an overall length of 0.96 in” (24.38mm).
The .25 NAA, created by North American Arms, is created by necking down a .32 ACP pistol cartridge and necking it down to accept a .251 diameter projectile, the same used in the .25 ACP cartridge, offered in a variety of weights in the 30-50 grain range, but offering much better ballistics than the .25 ACP. The .25 NAA offers velocities well above 1250fps with projectiles around 30 grains, with muzzle energy almost double that of the .25 ACP with the same projectile, and often times offers a decent increase in both velocity and muzzle energy than its parent case than the .32 ACP parent case.
The .25 NAA was originally called the 25-32 JBW, short for J.B. Wood, a gunsmith, author, and firearms expert and was introduced commercially in 2004 by North American Arms and Cor-Bon Ammunition (creators of the .400 Corbon cartridge), then changing its name to the current .25 NAA designation.