A steel spring with an unequal stroke designed for power tuning. It provides a muzzle velocity between 450 - 480 FPS (depending on the internal gearbox parts used). The fronts of the spring have been ground, which translates into its better operation.
![[SHS-08-001534] M140 Main Spring](http://forairsoft.com/cdn/shop/files/b1c7cd8565934f66b59ec40bb63f08097abd49ac_1152195333_1.webp?v=1780657124&width=1445)
![[SHS-08-001534] M140 Main Spring](http://forairsoft.com/cdn/shop/files/514c117ba6c5eced7861854bc10502e2900053fb_1152195333_2.webp?v=1780657126&width=1445)