Updated - 12.24.18 NOTE: This thread is NOT about dry firing or snap-caps. Glock armorer's or Expert comments are appreciated. Why? Because thread asks a Question. Responses that are a best guess, something pull from somewhere, and theories (by those that enjoy thinking) probably aren't going to answer the Question. Some of us appreciate our tools enough that we tend to think how to make them better. Is this the right part? (another reason for buying your *important parts from Glock vs someplace else)(another reason Glock should be selling *important parts to Glock Owners; ie, those that have passed at least a Glock Armorer's course, and are eligible members of GSSF.) (If you have ever been in Smyrna, you know that the place can be inhabited with some unhappy people, and those who live to give others a bad time. Smyrna doesn't sell *important Glock parts these days because they do not want to be bothered !)(Part of the problem is being buried by questions from curious, or un-informed Glock owners; and those who wished they owned a G-xx.) Maybe a Glock owner will sue Glock for being liable after denying the Glock owner access to an *important Glock pistol part. All this trouble because a few twerps don't want to be bothered. Mr. Glock, this problem is a bit short sighted is it not? ______________________________________________ Each Glock striker (<-an oops! correction: 12.24.18) is marked by a 'Caliber Group Code'; Code 1,2,3 have 1,2,3 straight cut marks near the 'front end' of the striker at 'cup end' of the striker spring. For example a 9mm and .380cal Glock firearms are in Caliber Group-1; while 10mm and .45cal (but not GAP) are in Caliber Group-3. The cut marks should make it easy to determine if the correct firing pin is installed in the Glock pistol (which may be yours)and(there may also be other ways to make the determination). (While Glock goes crazy with the endless G-models being built these days, some specs do not apply to all models). It makes me wonder though. Obviously, something about the firing pins in each Caliber Group, marked by 1,2, or 3 straight cut lines is different. In other words, forget about the factory markings for a moment; there *has to be a physical difference between strikers from group #1,#2,#3. What is the difference between stickers in the Group-1, Group-2, and Group-3?