I needed to put a lighter spring in my entire sized M16 A2 clone however it ran fine. Attempted once more Along with the 11.5" Comando Colt upper. No dice. Ran 500 rounds of wolf by it currently. Didnt harm the spring at all. Dupa logarea in cont trebuie accesat https://rafaelofvkz.hyperionwiki.com/1530696/frt_15l3_an_overview