Jun 11, 2004
#3
It's not a model issue.
It's related to several things.
1. Glocks don't tolerate
lead bullets well due to the rifling method used. Using lead bullets can cause a dangerous increase chamber pressures during firing.
2. .40 S&W ammunition is very sensitive to
bullet setback with the 180 grain loading being the most sensitive. Even relatively small amounts of bullet setback in this loading can cause chamber pressures during firing to rise to unsafe levels.
3.
Glock chambers are cut on the generous side which allows the brass to expand more than usual upon firing. This weakens the brass more than normal which means that using reloaded brass, or especially reloading .40 brass from rounds shot in a Glock can compound the #2 problem while also increasing the chances that the case will fail.
If you stick to high quality factory ammo with bullet weights under 180 grains and stay away from aluminum case ammo, you should have no problem.
Federal ammo seems to be over-represented in the failures associated with factory ammo--might want to stay away from them although I usually recommend their ammo in most cases.
For what it's worth, this phenomenon is not limited to Glocks. There have been kB!s in most brands--and in other calibers than .40. The .40 Glock does seem to get more than its share, but it's likely that some of this is due to the large number of these guns in service.