While working on my last column about general gun maintenance, it occurred to me that a lot of folks I talk to don't seem to know some of the simple, yet important points about how their Glocks work and how to anticipate or troubleshoot problems. I see a lot of them in classes, and Glock is claiming a 70+ percent share of the law enforcement market these days. With that in mind, here are a few things that might help you keep them running like...well, Glocks. I'm going to assume you can field-strip your gun correctly, so I'm not going into that specifically. And I'm not going to go into any further disassembly other than basic field stripping. If you discover by doing these checks that you have a potential problem, get the gun to your local Glock armorer.
Is it loaded?
First of all, since you have to pull the trigger to take a Glock apart, I better emphasize how important it is to make sure the pistol is empty before you begin. I'm still seeing periodic reports of people who didn't, with results from merely embarrassing to serious personal injury. For heaven's sake, triple check to make sure it is empty, and keep it pointed in a safe direction! Once you start the slide forward after releasing the slide lock, you may find that it binds up after moving only a fraction of an inch. This is particularly true if it has a New York-style trigger spring. That's normal. Just pull the trigger a second time and ease the slide off the frame. Once the slide is off the frame, hold it upside down and look at it from the side. You'll notice the back of the recoil spring/guide rod assembly is sitting up slightly from the half-moon shaped notch in the barrel lug, where you seated it when you last assembled it. What you are looking at is the normal operating position for that assembly. You want to make sure that you push it back down into the notch before reassembling the slide to the frame. If not, you can chip the edge of the rod and that will cause malfunctions. Most folks never notice this, because they usually take the slide components apart when they field strip the pistol. But if you ever remove the slide just to do something with the frame, you need to know about this before you put the slide back on.
What's that for?
While you have the slide in your hand, remove the recoil spring assembly and the barrel and hold the slide so it is muzzle end down and the bottom facing you. See the hole just the above the breech face? That's not a lubrication hole. It leads into the firing pin channel and is there to allow any debris in the channel to work its way out. If you put oil in there, it will literally gum up the works, as it holds in the stuff that would normally find its own way out. The firing pin assembly moves in its channel, inside a polymer liner. That provides all the "lubrication" needed. Make sure the firing pin is in its rearward position (sometimes it is protruding through the breech face when you take the gun apart). If you hold the slide vertically and push in on the firing pin safety (the round, spring loaded button), the firing pin should drop freely from its own weight into the "fired" position. If not, try holding the button in and move the firing pin gently up and down with your finger. If it is binding at all, the firing pin channel needs cleaning. (That's an armorer's job.) By the way, never push the firing pin to the rear against its own spring tension and allow it to snap forward. This can damage the firing pin safety, causing it to fail.
Another way to help keep junk out of the firing pin channel is to make sure you hold the slide "muzzle down" when you are cleaning the breech face and the extractor. If you hold it "muzzle up" (so it's easier to see what you are doing), dirt, solvents and lubricants can get into the channel through the hole in the breech face. Again, this is to be avoided. One last point on the slide operation: check to be sure the extractor isn't damaged. Look at it from the bottom, because it can look normal from the top, but the bottom edge, where most of the wear happens, can be chipped.