Unlike metal plastic deteriorate from the get go. Even if the plastic gun is never use and kept in perfect storage it will still deteriorate to a point of unusable.
Also plastic aren't good at extreme environments.
I stay away from plastic guns with the exception of Glock.
1000 Round Glock Torture Test
http://www.youtube.com/watch?v=0_JuF23qazI
AK jam then blew up a few rounds later.
http://rpginn.com/index.php?option=c...=605&Itemid=39
Extreme training with weapons.
http://thesurvivalpodcast.com/forum/...p?topic=1731.0