The .32 caliber pistol cartridges may not receive the attention that others do, but they are viable options for a wide variety of applications. Let's look into them a little.
This diminutive little gem started the .32 centerfire game way back in the late 1800s. It enjoyed vast popularity due to the numerous break top revolvers that were chambered for it. It is still stocked at many finer gun stores today because there are so many of the old revolvers still around. It is not a powerhouse, but its ballistics beat the .22 long rifle and the .25 ACP.
The .32 auto, aka .32 ACP, aka 7.65mm Browning is the original autoloader round designed by John M. Browning for use in small pistols. It increased the shortcomings of the .25 ACP without increasing the size of the guns chambered for it by much. It remains popular today. Interesting fact: this auto loading case has a small rim.
The .32 NAA is an odd ball. It was designed primarily for the Seacamp auto pistol. It uses the old trick of necking down a parent case to a smaller bullet size. The resulting velocity increase makes for a good increase in energy as well. The parent for this round is the .380. There were some retrofit kits made for the Makarov PM, but they have long since dried up. Wish I had one.
The .32 S&W long is simply a magnum version of the original .32 S&W. In most cases it simply uses the same bullet, but with a longer case to accommodate more powder.
The .32 H&R mag did not come on the scene until the 1980s. It is even longer than the S&W long and provides significant increases in power over the S&W long. You may notice that the weight of the bullets used in these revolver loads are around the same as the old .32 S&W.
The 327 Federal mag is the ultimate in .32 caliber revolver cartridges in terms of length and power. It roughly equates the energy of the .357 magnum.
Check out this site for all the numbers on your favorite cartridges.
http://www.ballisticsbytheinch.com/calibers.html
