another link for you: Tested: North American Arms .32 NAA Guardian "As noted earlier, you can acquire a Guardian chambered for the thoroughly capable (and commonly available) .32 ACP or .380 ACP rounds, but NAA has two other very unique options as well—the .25 NAA and the .32 NAA, and it is the latter of these we will be considering today. Both of these rounds, developed in concert with CorBon ammunition, feature “bottleneck” case designs. The .25 NAA is based off of the .32 ACP cartridge, is necked down to a .25-cal. projectile and is offered in the smaller-framed Guardian. The .32 NAA, offered in the larger .380 ACP-sized pistol, follows the same principle, but offers bigger punch and is based off of the .380 ACP case. Necked down to a .32-cal. projectile, the pint-sized powerhouse was designed to propel a 60-gr. projectile at 1,200 fps at the muzzle from the short 2.5” barrel of the Guardian, delivering 199 ft.-lbs. of energy. To put that in perspective, a comparable .32 ACP defensive round would push a 60-gr. projectile at around 1,000 fps and have about 130 ft.-lbs. of energy at the muzzle. A comparable .380 ACP defensive round would push a 90-gr. projectile at 1,000 fps and produce about 200 ft.-lbs. of energy at the muzzle." The .32 NAA round (left) is a bottlenecked cartridge based off of the .380 ACP (right) and necked down to a .32-cal. projectile. Blowback guns do have a bit more "snap" than other designs. Even a 9mm carbine in blowback has a bit of a concussion effect you don't get with the .223/5.56. If you haven't tried it, it is hard to describe.