We are getting asked more and more by people wanting to tune and adjust their FX air rifes using different hammer weights.

From this listing it is possible to select any weight hammer spring the FX make:
20271 – 6 grams –  hole
20463 – 10 grams  – no hole
19215 – 11.5 grams  – no hole
11540 – 12.5 grams  – no hole
17003 – 13.5 grams  – no hole

All designed to work with the same spring.

If using with an Impact you would need to drill a hole through the center of the ‘no hole’ versions.