Okay had enough on this what is it Saturday. It was a tough one. A friend of Gun Lab sent this to me to add to my reference library.
It is an early rear sight aperture spring for the very first AR-18’s. It never went into production. I am looking for pictures of these rifles or drawings of this rear sight. If and when I find it I will post it here.
As sent to taped to the card.
huh that is really different
5 years too late, but i noticed its the same spring design as shown in the ar18 patent drawings.