I needed to put a lighter spring in my complete sized M16 A2 clone but it really ran great. Tried using again Using the 11.5" Comando Colt upper. No dice. Ran 500 rounds of wolf by means of it nowadays. Didnt harm the spring in the least. But limiting it https://rare-breed-triggers18013.blogdeazar.com/36957285/rare-breed-trigger-no-further-a-mystery