Main spring for MB01 / L96 replicas from FPS Softair
The spring has been calibrated on the original VSR sniper rifle which gives up to 310-320 fps.
With shorter or longer barrels the performance will decrease or increase. The Other upgrade parts will affect the end FPS.
The FPS spring is 100% Made in Italy. The material used is steel wire burnished and pre-hardened carbon steel with the addition of silicon and chromium EN10270 / 2. The spring has coils with a variable pitch in the central area and in that in contact with the spring guide and undergoes a process of grinding the two ends which guarantees optimal performance in the compression phase.