Couldn’t think of a more appropriate title, but I suppose the one above is true enough.
All equipment can fail, especially firearms. It is why we do preventive maintenance.
Shot my 5.45 AR a couple of weeks ago, everything was fine then. I set it aside and put off cleaning (I could because I was using non-corrosive ammo). When I went to clean it yesterday I found the barrel nut was now loose.
Now it is likely that just the process of heating and cooling from shooting eventually broke the barrel nut loose, but it is also possible that the nut or the upper has cracked. Possibly even the threads on the upper broke. So, I get to pull it apart and check.
Things can fail, even when we are not looking. Especially when we are not paying attention.
I am reminded of a shooting class I was in. One of the students was having an issue with their pistol. The instructor was CCWing that same model revolver as his second carry gun so he pulled it out to let the student use it. Much to both of their dismay, that second gun wasn’t working either.