If you shoot enough you will eventually encounter a malfunction.
When your firearm stops working, the issue could be any number of issues, bad ammo, bad mags, mechanical failure, user error, etc. All these malfunctions can be placed in four categories.
1. Action closed malfunctions. When the slide or bolt is closed, often you will hear a click when you were expecting a bang. These malfunctions are usually cleared using the “Tap Rack Bang” technique.
2. Action open malfunctions. The slide or bolt is open from an issue such as double feeding or failure to eject. Clearing these malfunctions generally involve removing the magazine, clearing the action, and reloading. The acronym S.P.O.R.T.S. is often thrown out in reference to these issues.
3. Malfunctions unique to a weapons system. These include rare problems like the Glock “Phase three” malfunction, or the AR15 brass over bolt malfunction. These generally require familiarity with the weapon system and that particular malfunction to clear quickly.
4. Malfunctions that require tools, disassemble or replacement parts. If you have a squib, or if your firearm is shot by enemy fire, or should a critical part(like a firing pin) break, your firearm is rendered non-operational. In a fight, you have to make the decision whether to retain this broken firearm or not, then either transition to another weapon system, or break contact and run away. Outside of combat, a day at the range can be ruined if your firearm is non-functional and you don’t have a way to fix it, or anything else to shoot.
Continuing on this fourth type of issue. I had a range day ruined when I had a case head separation with a round of Black Hills match ammo. My broken case extractor sitting at home didn’t do me much good. I’ve seen broken extractors in bolt actions prevent people from accomplishing what they wanted to do. As for the picture above, that was an amazing fluke. The slide stop on a CZ52 got stuck below the magazine follower. Techniques like Tap-Rack-Bang or S.P.O.R.T.S. isn’t going to help you in a situation like this.
In conclusion, there are issues which will take your weapon out of action. At those times you need to quickly decide if you can use your back up weapon, or if you need to run.