Airsoft Master Gunsmith (AMG) "Winter Use" Hammer Spring for Airsoft GBB Series (Type: WE M4)

"Ignore the 1 star review. This is NOT an all year round hammer spring. I use the winter spring in my MSK for it's intended use, to not expel excess gas during cold winter months when your pressure will be lower. If you use it in the summer, you will be more likely to get light strikes and have the issues noted. Keep your stock spring in a place you won't lose it, and use this to keep running your gbb's during the winter months like advertised.

"AMG line is bad at their job, the AAP spring is so weak it will light strike the magazine and it will not work! In all honesty their entire line of AAP parts have been a huge let down!