Bottlenecked Handgun Cartridges
From the late 1800s until the 1930s, bottleneck handgun cartridges were common, primarily in pistols. Handguns firing bottlenecked cartridges were used by many nations armed forces up until the 1930s (the Mauser C96 “Broomhandle” most popularly; even Winston Churchill and the British used them), and pistols firing these cartridges were chosen as the military sidearm for Russia and Japan in ww2.
To the left you see a picture of the 7.62×25 Tokarev, 7.63×25 Mauser and 7.65×21 Luger cartridges. The bottleneck design for handgun cartridges faded after the 1940s (with 2 exceptions), only to make a minor comeback in the last decade or so. We will get to that later.
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Why use a bottlenecked cartridge at all? Because you can put more energy behind the bullet, in the form of velocity. At the time, bullets were all round-nose jacketed designs, so expansion wasn’t the goal. Also, feeding reliability is improved, since the little bullet has a big hole to get seated in. Take a look at the specifications on the common early bottlenecked cartridges:
The Mauser bullet really moves; and the Soviets built upon that cartridge to make the Tokarev which is even faster. The cartridge dimensions are almost identical; the Germans ordered a million rounds of “obsolete” 7.63×25 Mauser ammo in WW2 (even though 9mm was the standard cartridge) so that they could use it in captured Soviet handguns and PPsH41 submachineguns. The reverse would not be good, as the Tokarev round is much hotter and would be a serious safety hazard in a gun chambered for the Mauser round. In any event, the German and Russian rounds did pretty well on penetration.
The other thing you will notice from those specs is that the Japanese cartridges are pretty anemic. The Nambu guns were, and are, odd. Some models would (allegedly) fire if you pressed the exposed sear on the side of the gun. Japanese sidearms do not have a great reputation, but some claim that the trigger on a Type 14 Nambu is superb.
For the most part, dramatically bottlenecked cartridges were used in self-loading pistols. There are some bottlenecked revolver rounds, such as the .32-20 and .44-40, but these are pretty gentle bottlenecks, almost a taper, really. An uncle of mine carried a .32-20 S&W revolver with him to the Pacific when he was a SeaBee in WW2; it makes some noise when you fire it, as you would expect from a rifle cartridge fired in a handgun. From the end of WW2 until very recently, there were only 2 bottlenecked handgun cartridges developed for wide commercial use: the .22 Remington Jet (aka .22 CenterFire Magnum) and the .256 Winchester Magnum.
Both were formed from .357 Magnum brass, and both were really niche products. Just look at the differences in shoulder location and cartridge taper. The .22 Rem Jet was only offered in the rare S&W Model 53 revolver (a Marlin lever action was planned but never appeared) and the .256 Win Mag was only offered in a single-shot version of the Ruger Blackhawk revolver and the T/C Contender (a Marlin “Levermatic” rifle and an M1 carbine variant were also made).
Why were so few guns made for these ? And why were both .256 Win Mag handgun offerings single-shot? Apparently, setback is a problem with drastically-bottlenecked cartridges in revolvers. The cases are forced backwards when the gun fires, and the cylinder locks up. While that is not a factor for self-loading pistols, it is a serious drawback in a revolver which really doesn’t have any way of holding the cartridges securely in their chambers while allowing free movement of the cylinder (and facilitating a reasonable trigger pull). I hear that this is still a problem with .17HMR revolvers today. The fix on the Model 53 was to clean the chamber of all lube to decrease the chance of setback.
The Model 53 revolver was available with a second .22 Long Rifle cylinder; it also had adapters for the .22 Rem Jet cylinder that would let you shoot a .22 LR cartridge in it.
The .256 Win Mag was offered in a Ruger Blackhawk that was converted to a single shot using a flat “cylinder”. Since it doesn’t rotate, it can be made to fit tighter to eliminate setback.
Well, today we have been introduced to a pretty wide assortment of new bottlenecked handgun cartridges, including the .17HMR that I mentioned above (most people rightly consider the .17HMR a rifle cartridge, so I will not be including it in this chart):
I tried to show middle weights for the parent cartridges, not the heaviest and not the lightest available. All of these cartridges are based on existing cases, and all offer significantly higher velocity than their parent cartridges, using smaller bullets. The most popular of these new bottleneck cartridges is the .357 SiG; it has been adopted by multiple law enforcement agencies.
Velocity is critical for making expanding (hollow-point) bullets expand. The larger the parent round, the less bullet weight you lose (as a %) when turning it into a bottleneck round. The .25 NAA loses almost 50% of its bullet weight when compared to its parent, but the .400 CorBon only loses 25%.
Is the trade-off worth it? In the case of the .400 CorBon, absolutely. Still have plenty of bullet weight and diameter, but a lot more velocity. For the .25NAA, it’s probably a wash. Even if it expands, it’s not going to touch a lot of tissue because it doesn’t have a lot of diameter and it won’t penetrate very deep because it isn’t very heavy. The .32acp has a pretty good record of stoppages on the street (the Winchester Silvertip, according to Marshall & Sanow’s stats), and the .32NAA gives a lot more speed to the same size bullet. And I don’t trust .380 bullets to stop a cretin. They just move too slow and weight too little for their diameter. Shallow penetration and iffy expansion.
But, in any event, we have some new rounds to argue about.
When it comes to handguns, I am not an advocate of heavy & slow bullets (they don’t expand). Nor do I put my faith in light & fast bullets (they don’t penetrate). I prefer medium-weight bullets (within a particular caliber) moving fast enough to expand, and I would sacrifice some caliber or bullet weight to get extra velocity. Given the choice of a .32acp carry gun or a .380, I would carry the .32.