The 140 m / s FPS spring has been calibrated on the original mechanics of the Well brand MB03 rifle.

Of course, with shorter or longer barrels the performance will decrease or increase, so you will switch to the harder or softer calibration.

In the calibration process, the thickness due to the bearings was not taken into consideration, therefore, with the same initial conditions, an increase in performance of about 2.5 m / s for each bearing must be taken into account.

The FPS spring is 100% Made in Italy and was made in collaboration with leading companies in the sector.