last night I was working on an AR. Before I started I looked down on my work bench and saw a spring that I do not recognize......no idea where it came from. It's about 3/8" long x ~.010 dia. and very fine wire. The last three guns I have worked on were an AR (I'm about 99.999% sure it is not from that), a Browning 1911 380 and a KelTec PMR 30. Any thoughts where a spring this small might come from?