Originally Posted by
GJM
It seems like everything about the M is happening slowly. Slow to get initial information, slow to get even a picture, and now slow to get information on the resolution of problems with the Indy pistols. I heard this afternoon, that the M pistols haven’t gotten back to Glock yet, no doubt going cheapest and slowest way back. At this rate, we will have to wait for a story in Guns & Ammo magazine for an update. In the mean time, since various things are pointing towards a reversed slide lock, I decided to do a deep dive on the slide lock. While I routinely work on my Glock pistols, and have a spare slide lock or two in my parts kit, I have actually never removed a slide lock from the frame. This is what I learned.
First, can the slide lock be installed incorrectly? Yes, it fits with the ridge on the slide lock part oriented either way. The correct way is with the "ridge rearward," and “ridge rearward” is frequently taught in their armorer class to remind people on how to insert the slide lock correctly.
Second, what happens when the slide lock is inserted incorrectly? The pistol still fires, and should continue to, because of some interface with barrel, and other parts. (I think Tom Jones can elaborate as the fine technical details went over my head earlier.) However, when the slide lock is inserted incorrectly, the slide may come off when dry firing and administratively handling the pistol. No idea if a tight fitting holster can cause the slide and receiver to separate.
Third, how are the pistols assembled at Glock? There is a large, open assembly area, where different individuals do different parts of the assembly process. So, one assembler doesn't do the whole pistol, but rather one individual does one part of the process. So likely only one or two assemblers inserted each slide lock in the Indy batch of M pistols.
Fourth, what happens after the pistol is assembled? Each pistol is placed in a test fixture. A proof load is fired, and that proof load is about 30 something percent higher pressure than a max commercial 9mm load. After the proof load, 5 or 6 rounds are fired, and possibly (but I haven't confirmed this last part) the last cartridge fired is also a proof load. At that point, the slide locks back in the test fixture, the tech removes the pistol, drops the slide, and presses the trigger.
Fifth, what happened when the pistols got to Indy? I have no idea whether the pistols were disassembled, whether each was fired, each was dry fired and/or administratively handled, before being issued to an officer.
So, logically, these seem to be the possibilities, if the problem was the slide lock was installed improperly:
1) A Glock assembler or assemblers, whose job is to install the slide lock, put it in backwards and didn't realize it. Other people further down the assembly line failed to notice the slide lock was inserted backwards.
2) Glock techs who test fired the pistol, and then dropped the slide, failed to notice that the slide separated because the slide lock was installed improperly.
3) The person unboxing the pistol failed to notice that the slide separated when dry firing, or acted funny when taking it apart, since slide lock levers on each side can be pushed down for disassembly without retracting the slide as with a normal Glock.
4) An armorer at Indy disassembled pistol and reassembled with slide lock backwards. No idea whether the pistols were disassembled there.
5) An individual officer disassembled pistol and reassembled improperly.
What is interesting, is if the problem was the slide lock was installed backwards, regardless of who did it, it may well be difficult to know who, since it takes literally seconds to switch it back. When the first officer came in with a M in two pieces, there may well have been puzzlement, but by the time the second pistol came back, the problem was likely known. It will be interesting as they try to figure out who did what.
I enjoyed learning more about Glock’s process for assembling pistols. In particular, the test firing, including the proof round, and additional rounds, was complete news to me. Of course, if it turns out to be a design flaw or problem with the slide lock part or spring, assembly may not be a factor at all.