Sunday, September 03, 2006

What we know that just ain't so

Sometimes the things we think we know just ain't so. Or at least they ain't so any more. When I first became interested in firearms I read a book by Chuck Taylor called The Complete Book of Combat Handgunning. It was a good book filled with good advice that was mostly current as of the year of publication, 1982. However there was one thing in it which came to puzzle me somewhat as I became more and more familiar with firearms and began to load my own ammunition. The author said that while the .357 Magnum was a good manstopper it should not be used for defensive purposes in a revolver with a less than 6" barrel. The reason given was that the shorter barrels caused the round to lose so much velocity that the .357 round would wind up traveling little faster than a standard .38 Special.

As I said this puzzled me because as a handloader I know that the velocity drop, while measurable, is not that great. Yet I was told by people who I assumed knew what they were talking about that the velocity data was worked up in test guns having barrels over 8" long and going below 6" would cost too many feet per second.

This did not make sense because a large number of law enforcement agencies at the local, state and federal level had adopted the .357 Magnum in the 4" barrel configuration and were very happy with it. In fact no less an authority than the FBI had adopted the .357 Magnum. The stopping power statistics compiled by Mossad Ayoob indicated that it was the best handgun round available with a one-shot-stop ratio in the 90% range, even better than the .45 ACP. Remember that this was in the early to mid 1980s before the new crop of bullet designs like the HST.

I filed this discrepancy between what the experts said and what proved true in the real world away and didn't think too much of it until recently. I bought a copy of Chic Gaylord's classic Handgunner's Guide which was published around 1967 and found the same warning about using a short barreled .357 with the same reason given - loss of velocity.

I decided to a bit of research to try and pin down the origin of this myth and found out that it wasn't a myth, at its origin. You see the .357 was invented in 1934 by Smith and Wesson at the urging of firearms legend Elmer Keith. Keith liked the .38 Special revolver, but didn't think the round had enough power. To create a more powerful cartridge in the same caliber the case was lengthened by a bit over 1/10 of an inch and the new cartridge was loaded to around twice the pressure of the .38 Special. The resulting round is flat shooting and has excellent stopping power when expanding bullets are used.

Now here is the interesting part. In 1934 the science of making smokeless gunpowder was not nearly as advanced as it is today. In order to achieve the most efficient loading to produce the maximum velocity the original .357 Magnum ammunition was loaded with very slow burning powder. Slow burning powder is more bulky than fast burning powder which causes more of the available area inside the cartridge case to be filled and leads to more even burning and gives more consistent velocity which in turn gives more consistent accuracy.

The drawback to slow burning powder is that they need long barrels so that all the powder can burn before the bullet leaves the muzzle. A shorter barrel could mean that you only get 75% of your powder burning while the bullet is still in the barrel and the expanding gasses can add velocity to the bullet. Short barrel + slow burning powder = powder being wasted on a big fireball and nothing else.

Now fast forward even to 1982. Much better powder is available which bridges the gap between the very fast burning and very slow burning powders. This allows .357 Magnum ammunition to be created which can be fired from a short barreled revolver and still retain enough velocity to hit hard, penetrate deeply and expand impressively. This contacts and destroys lots of tissue, lets out lots of blood and generally ruins your target's day.

So the data that the .357 Magnum needed to be fired from a long barreled revolver was not a myth, it was simply obsolete. What happened is that knowledgeable men took a bit of information which was valid in its day and enshrined it as though it were holy writ, handed down from On High by the Archangel.

The lesson here is never stop asking “WHY”.