The Action Army M120 Upgrade Spring for Tokyo Marui VSR-10 Airsoft Sniper Rifles is engineered for durability, consistent tension, and reliable FPS output. Compatible with Tokyo Marui VSR-10 and other VSR-based airsoft sniper rifles, this heavy-duty steel spring delivers an estimated 360–450 FPS depending on your barrel length, hop-up unit, and internal air seal. Ideal for airsoft players looking to upgrade their bolt-action sniper rifle for increased range, muzzle velocity, and shot-to-shot consistency, the Action Army M120 spring is a trusted choice among competitive and field-ready VSR-10 builds.