Reloading the Glock 40
Part of the problem that Richard Lee has encountered may have to do with the 40S&W in the Glock as well as the use of lead bullets. You never want to attempt to shoot lead bullets in a Glock. The fouling can be really bad to the point that pressures run dangerously high. Other than these factors I have had no problems reloading fro my Glock model 19. I just stick with jacketed bullets.
The following is from one of my other posts: ...I've run into this myself. You didn't mention the source of your brass. If you are using once fired range brass or once fired brass from some other source, it is possible that some of your brass may have been originally fired in a Glock. You can recognize brass that has been fired in a Glock pistol by the distinctive mark made on the primer by the striker...V-shaped firing pin indention surrounded by a retangular pertrusion. Glocks are very good pistols but the design of the pistol in the 40 S&W chambering doesn't fully support the case head. This sometimes results in the deformation of the brass just in front of the case head; known as the web area of the case. With very hot loads, the deformation can be so severe that the resizing die will be unable to return the case to a dimension that will permit chambering after subsequent reloadings. People attempting to fire reloads in their 40 S&W Glocks have occasionally had the case head blow out completely, with reloaded ammunition, sending sufficient gas pressure and burning gunpowder downward through the magazine well with enough force to completely blow the magazine out of the pistol causing damage. If you research this subject on the web, you will see some folks refering to this problem as a "Ka-boom" or KB for short. BTW...Glock doesn't regard this issue as a problem, as their pistols are intended to be used with good quality, new, factory ammunition. Most manufacturers take the position that the use of re-loaded ammunition voids the factory warranty. I might also add that the "Kaboom" problem occurs very rarely, if at all, with new factory ammunition. Hope this helps.
GHS