The SI Carbine Flatwire Spring is an economical, easy upgrade to any AR system with a carbine buffer system. The flatwire spring increases service life of the platform, smooths out the shooting cycle, and greatly outlasts the stock spring. Increased bolt load, in addition to decreased compression force increases reliability in cycling.
Specifications:

Type	Recoil Spring
Model	AR Style
Dimensions
Size
Material	17-7 Stainless Steel
Action
Trigger
Safety
Thread Pattern
Finish	Stainless Steel
Bolt Type
Hand
Hammer Type
Max Capacity