Is it common that commercial snap caps have only Delrin in primer pocket, solidly in place, with no heavy spring in back of it? If so, won't the delrin dent from firing pin blow, and eventually increase dent size until the delrin is no longer doing its intended job, due to large indentation, or am I wrong on this? Since I have a small precision lathe, I have always made my own snap caps, by drilling out the primer pocket, and making a two diameter delrin insert, with major diameter a slip fit in the cartridge, and the minor diamter a slip fit in primer pocket hole, so this delrin will move when struck by the firing pin. Now, behind this delrin, I insert a heavy coil spring and epoxy in another delrin piece to hold spring in place, under pressure. This allows delrin to move, but at the same time to cushion the firing pin blow, and all works well. I have never bought a commercial snap cap, so know nothing about them. Is one available, similar to what I make?