Leon explains using Green Gas on plastic airsoft gas guns if they will be prone to cracking or not... "This video explains the different gasses for polymer slide airsoft guns. Your slide may be prone to cracking using green gas or anything more powerful, you should use weaker gasses however using green gas will not break your airsoft gun unless you use green gas regularly.

Disclaimer: I am not liable for any damages caused to your airsoft guns, nor do I condone the use of green gas on polymer airsoft guns, read your guns description and manual."