Is plastic used for guns

Plastic has been used as a PART of guns for several years- I have a 1943 target rifle with a plastic trigger guard- and the M-16 rifle has a plastic stock and forearm. Much of the frame of the Glock pistol is a polymer (plastic). However, misinformation has been published by folks that should know better about "plastic" guns that are ALL plastic, and not detectable by normal means. These do not exist, and in fact are unlawful to make. I have seen ONE all plastic firearm- made as a clandestine, 2 shot firearm for the CIA. It was experimental, and never made in quantity.