Sunday, March 03, 2024

Narrow Focus Cartridge

Taurus 327 Defender TORO

When the .357SIG cartridge was still in fairly common law enforcement use, just the mention of it was a red flag for a certain sort of old-timer on the gun forums.

Someone would refer to it as "Designed to be the equivalent of .357 Magnum, but in a semiautomatic pistol" and they'd be buried under an avalanche of replies from posters with user names like "WheelgunFan" and "SixFerShur" and "Cowboy Bart" pointing out that the revolver load could fire 158gr and 180gr and even 200gr bullets at velocities that were simply not possible with the bottlenecked pistol cartridge.

Which was fine and good, but the .357SIG was intended to duplicate one specific .357 Magnum loading for one specific purpose: The 125gr JHP load that had such a good reputation with some law enforcement departments, and especially Highway Patrols.

Similarly, the .327 Federal Magnum is not designed to be a "do everything" cartridge. It's designed to do one thing, and that's offer pretty much identical terminal ballistics to the 9x19mm 124gr +P loads that are pretty much the benchmark loads for law enforcement today.

.38 Special doesn't do that. People tend to equate .38 Special and 9mm, but the fact of the matter is that 9mm... especially in +P form a lot closer to .357 Magnum than it is to the old .38 Special.

Witness the following maximum pressures:
  • .38 Special: 17,000psi
  • .38 Spl +P: 20,000psi
  • 9x19mm:  35,000psi
  • 9mm +P:  38,500psi
  • .357 Mag: 35,000psi
The problem is that .357 Magnum is limited to five shots in small frame revolvers. So the .327 Federal Magnum was designed to offer six shots in a Ruger SP-101 (or the newer Taurus 327) that gave terminal performance equivalent to the common medium-velocity 125gr .357 loads... and, by extension, the 9mm +P 124gr. It does this by virtue of operating at higher pressures (40k psi) and the 100gr .312" bullets having slightly greater sectional density than the 125gr .357" ones.

I suppose if you really wanted to hunt rabbits or target shoot with a .327 Fed revolver, you could load it with .32 S&W Long or .32 H&R Mag, but the .327 Federal Magnum cartridge itself is really only intended to do one thing.