The insides of a Mauser pistol are surprisingly complicated, especially for such a compact little pistol. I found that out the hard way when I realized that if the trigger bar isn’t lined up just right, it won’t engage the sear at all. That led to some frustrating moments with a completely dead trigger. I ended up taking mine apart a couple of times before I figured out that the slide wasn’t fully engaging the trigger mechanism. Just a tiny bit off, and it wouldn’t fire at all.
Another thing I learned the hard way is to keep an eye on the firing pin spring. Mine was pretty weak after sitting in a drawer for years, which meant it didn’t have enough oomph to actually hit the pin. Swapping it out made a world of difference. And don’t forget about the safety lever. It’s easy to think it’s off when it’s still partially engaged, especially with these older models.