FX Maverick/Wildcat mk3 gurus question?

They are supposed to leave the factory with a 13g hammer weight and a 52mm spring. I dont think the actual spring rate is different, just shorter. Sometimes FX lets the ship out with the wrong parts.

Ok thanks. Just thinking of buying a .25 barrel just not sure if I would need a different spring in addition to the lighter hammer.
 
Yeah you will likely need the longer spring as well. Using the short spring with the shorter weight face will leave you with lighter strikes. In the 30Cal they used the short spring because there isnt a lot of room for coil bind plus the thicker hammer weight face. I tried using the long spring with a 13g hammer weight and got fps all over the place. If you plan to run the same or similar reg pressures with the 25Cal you probably wont have to change any parts. Its all about fitting the hammer system power to the reg/valve resistance I have found. Coincidentally my Wildcat 500mm is setup as a 25Cal right now with the lightest factory weight (~9g) and long spring; like you would find in a 22/177Cal rifle. I only need ~45fpe with Hades so this range works well for me.