Unhappy Glock

American Handgunner, July-August, 2004 by Alex Hamilton

These blow-ups are always interesting to inspect so I thought you might like to see one. The Glock pictured is a Model 35 in .40 S&W. It was brought into my shop by an experienced shooter who wanted an analysis of exactly what happened. The first thing I did was examine the custom, match-grade stainless steel barrel at the halfway point, in search for any kind of bulge which would show the failure was caused by an obstructed bore. After careful examination, no bulge was found. Next, the barrel was tested for proper heat treatment on a Rockwell Hardness tester. The barrel checked out at 40C to 42C which is right on the money for a good, long lasting maximum tensile strength match barrel (Glock factory barrels check out at around 32C. A file is 62C.)

Further examination showed the barrel burst from the rear first, blowing the top of the slide up and shearing the locking lug off the bottom. The barrel then ripped apart separating the top from the bottom, hot, high pressure gas went down into the magazine well shattering the magazine, the left rear frame rail sheared off where it was joined to the plastic frame--a testament to the strength of the bonded Glock frame rails. The trigger surrounding the passive safety was blown off, stinging the shooters finger, the extractor blew off, the slide flew forward off the lower unit along with the two pieces of the barrel, and the internal parts were destroyed and bent. Everything in the upper unit was lying on the ground in front of the "ringing-eared" shooter. I'll bet that was an exciting second or two, eh?

All of the symptoms pointed to a catastrophic failure due to an overloaded cartridge that produced pressure far exceeding what the barrel and slide could stand. When you are loading on a progressive loader please concentrate on each and every cartridge in the powder loading station, If the loader stops or jams before pulling the lever down you must remove the cartridge at the powder stage, empty its powder and recharge. Case overload detectors are always helpful. And here's the proof.