A steel spring with an unequal stroke designed for power tuning. It provides a muzzle velocity between 500 - 520 FPS (depending on the internal gearbox parts used). The fronts of the spring have been ground, which translates into its better operation.
![[SHS-08-001533] M150 Main Spring](http://forairsoft.com/cdn/shop/files/b583b998814ec3a26cb584025baa88821598f94a_1152195332_1.webp?v=1780657268&width=1445)
![[SHS-08-001533] M150 Main Spring](http://forairsoft.com/cdn/shop/files/5aa1ddbda99b5051e7a09b296f0fc3876d4273de_1152195332_2.webp?v=1780657270&width=1445)