From what I've read, these small special hardened parts were one of the most difficult parts to make and most problems had to do with tempering of the completed part. There had to be tons of these things made and the average one carbine guy will never need more that a couple.
I work on watches and losing small parts is a common thing. I use one of those donut shaped magnets that roofers use to police up dropped nails (when they do police up nails). You just tie a piece of string to the magnet and tow it around the room, carpet or whatever. It picks up everything that is ferrous. Works like a champ.