Monday, November 12, 2007 Rama: When a Glock goes kaBOOM! By Karlon N. Rama Stage Five
THE .40 cal. is enjoying immense popularity nowadays and two guns of Gaston Glock—the Glock 22 and 23—are among the more well-liked platforms.
But comparative to the caliber’s fame and Glock’s repute, also exists is the concern that the gun allegedly blows up in one’s hands when fired using certain ammunitions and under certain conditions.
I know of three Glock owners, one of them is a very good friend, who has had to part with their firearms under such explosive conditions.
It would only be fair to add, though, that I know a lot more owners of .40 cal.-chambered Glock who have not encountered such problems and who continue to shoot their handguns free from worry.
Still, I recommend both the caliber and the weapon platform to others only with the strong caveat: 1.) Use factory ammunition or, at the very least to stay away from lead-cast bullets; 2.) Constantly clean the gun and make sure that it is in perfect order; and 3.) If possible, buy after-market barrels from such makers as KKM or Wilson.
American firearm writer Dan Speir has studied the subject extensively and coined the shorthand “kB!” for “kaBOOM” that, he says, “is the written representation of what happens when one has a catastrophic explosive event on one’s Glock.”
From the work of various sources, as well as observations from local gunsmiths and some Glock-owners themselves, we can identify certain elements that jointly contribute, or if the gun owner is terribly jinxed, independently cause the catastrophic “kB!”
The first becomes evident after a mere inspection of either the Glock 22 or 23 barrel—they are exactly of the outer same dimension as the Glock 17 and 19 barrels that are chambered for the smaller 9mm round.
One story goes that Glock, in the mad dash to come out with a .40 cal. platform without losing much market share to Smith & Wesson (the company that originally developed the caliber) built their .40 cal. series around 9mm barrel given a larger bore diameter. The result is a barrel with thinner walls.
But does thinner barrel walls equal to weaker structural integrity? Not necessarily or at least not in levels which, by and in itself, will cause it to split open while being fired, says industrial engineer and Glock owner Andy Chua of the Kamagong Gun Club.
The 9mm and the .40 cal. round operate in about the same pressure levels—35,000 pounds-per-square-inch.
And since the 9mm-chambered Glocks came first—not to mention how there haven’t been any documented problems about this particular platform, well at least not in the same level as their .40 cal.-chambered counterparts—we can surmise that the Gaston Glock’s engineers made their 9mm barrels with such dimensions for a reason—optimum structural integrity.
However, the same brilliant engineers must have thought about the same integrity issue when they elected to ream 9mm barrel blanks with.40 cal. bores. And that the fact that they pushed through with it to birth the Glock 22, 23 and the subcompact 27, we can surmise that they thought the tradeoff wasn’t too significant.
The .40 cal. Glock barrels, says firearms instructor Dr. Tyrone Mercader, is “blue pilled” for at least 50,000 psi. The estimated additional 15,000 psi rating is for safety.
This brings us to the second point.
It only needs 5.2 to 5.8 grains of Vihtavouri N320 gun powder to launch a 155-grain .40 cal. bullet at velocities of up to 1,106 to 1,177 feet per second from a gun with a four-inch barrel like the Glock 22.
In contrast, an empty .40 cal. cartridge, also known among hand loaders and shooters as the brass or shell, is .423 inches wide in the mouth, is .424 inches wide in the rim and stands .850 inches long. It has a capacity of 21 grains of water.
The brass’ capacity, as against the actual amount of gunpowder needed in shooting the round, is so large that it is almost impossible to visually check to make sure that a cartridge hasn’t been inadvertently double or even triple loaded by a hand loader.
An accidentally double loaded .40 cal. cartridge can push a 155-grain bullet up to velocities of 2,200 feet per second for chamber pressures reaching 70,000 psi – well into “rifle load” country, notes Mercader, and well above the “blue pilled” 50,000 psi ceiling.
