Can anyone shed some light on the markings on the hammer of my NFA registered receiver M16A1 shown below.

Thanks in advance!

http://ospreyanalytical.com/other/hammer2_M16.jpg

It would be good if your picture was in focus

height=8

Quoted: It would be good if your picture was in focus

That it would, I must apologize for the lack of quality; I will get another image up ASAP.

In the meantime perhaps someone is familiar with the use of such pentagonal & circular markings?

The circle with a C inside is typical of Colt M16 hammers. I'm not sure about the pentagon. Maybe it's a CIA hammer.

All joking aside, it is a Colt hammer if that is your question, but there isn't a lot of information that I'm aware of on the sub contractors of M16 parts. We know most of the companies that provide the forgings for receivers, the contractors for most barrels, and the different magazine contractors, but most of the other parts, such as hammers, triggers, etc., are very difficult to nail down. I think Colt subcontracted those parts out from time to time as they did other components.