FSC/TCP/VKS CUSTOM BOLT SPRING

A custom spring designed for the FSC/TCP/VKS. With a spring rate between the stock spring and a VKS spring, the custom spring provides the benefits of both. More resistance than stock for conservation of CO2, and less spring rate than a VKS to increase power. Typical gain over VKS spring is 2.5-3%. It all adds up- and every bit counts. Custom made to our specification is the USA.