A drop in hammer spring replacement which allow your VFC AR/APFG MCX to be more gas efficient and work better in colder weather.

From Waldo Dynamics

The One Spring You Need For Efficiency All Year-Round

Boost your VFC GBBRs performance year-round with the Waldo Dynamics Winter Hammer Spring, precision-engineered for the VFC AR and MCX GBBR platforms. Designed at 75% strength, this hammer spring delivers improved gas efficiency over the stock component but can still be used all year around. 

That's right; despite this being an overall weaker hammer spring you can still use this in peak summer on your usual green gasses. We performed some extensive testing in the last few months in climates all over the world and found no issues with it's capabilities. This is just a very simple upgrade over the stock spring that can be installed within 3 minutes (video guide here).

Finished in a distinctive blue coating, the finish not only reduces friction (giving you a butter smooth shooting experience) but it also helps you tell it apart from other springs you may have.

This product is compatible with;

- All VFC AR based GBBRs (KS1, BCM, URGI, XM series etc)
- VFC 416 GBBR
- APFG MCX GBBR