I think I have two magazines from the expendable mag project. The M16 magazine I am positive, the M14 mag still needs to be confirmed.
The 20 round M16 mag was produced by Aircraft Armaments Industries in Cockeysville, Maryland. The idea was the magazine came preloaded with ammunition and was thrown away after use. This magazine is well made.
The 30 round M14 I cannot confirm as being part of the project yet; it came from a former employee at Rock Island Arsenal who had no knowledge of the project. Rock Island played with lots of stuff during the 1970's so until I can confirm otherwise my assumption is this 30 round mag was part of the project. This magazine is not well made and looks like a one time use item.
The price of plastic during the oil crisis evidentually killed the idea.