Replacement hammer spring (also sometimes called main spring) for the FX Panthera air rifle.

Factory Spec High power: Select Part 2604. 52mm

Stronger 55mm spring: Select part 11500 – longer spring fitted to earlier impact models, we have customers using this spring in other rifles for tuning.

For UK limit Sub 12ftlb (all calibers): Softer but lomnger spring – 16024