The victim of this story is my new CZ 75D, PCR. A wonderful pistol and I'm very pleased with it. However, all of my modern firearms have been disassembled, polished, smoothed internally to make them as nice shooting as possible. SO, I looked at several U tube videos to gain knowledge. The basics are fairly simple and easy. Then I come to the "Sear Cage". This is a metal part containing the sear, decocker, firing pin lifter, and three springs. None of the springs want to go into place, all want to pop out and disappear into nether areas of my shop. But I was smart and had been warned and had spares on hand. I needed them. It seems that you can get two of the springs in and the 3rd makes life difficult. Did I mention that one of them is a tiny little spring that is almost invisible and has wings. Understand, I have built from parts, a match 1911, tuned dozens of S&W revolvers & 1911s, several Browning Hi Powers, built 3 AR rifles, several bolt rifles & many .22s, so the internals of firearms is not a fearsome mystery to me. That Sear Cage was 4 hours of "fun". It finally is together, polished and smoothed BUT with an education and a couple of springs in my shop that will be found someday when I don't need or want them.