ISMI 1911 Hammer Spring / Mainspring – Premium (15 Pounds)

Reliable Hammer Energy for Your 1911

The ISMI 1911 Hammer Spring / Mainspring – 15 Pounds delivers strong, consistent hammer energy. It keeps the hammer cycling smoothly and maintains predictable tension. As a result, your 1911 feels stable, responsive, and ready for every shot, whether at the range, in competition, or during tactical use.

Premium Silicone Chrome Alloy Construction

ISMI builds each mainspring from high-grade silicone chrome alloy. Unlike traditional music wire, this alloy resists fatigue and holds its shape through heavy use. Therefore, the spring provides steady pressure and long-lasting reliability. You can trust it to keep your pistol performing at its best, shot after shot.

Advanced Multi-Stage Production

ISMI strengthens each spring through a proven multi-stage process.

• Heat treating creates even strength throughout the alloy

• Shot peening improves surface toughness and wear resistance

• Stress relieving maintains consistent tension over time

Together, these steps produce a mainspring that withstands frequent cycling and heavy use.

Engineered for Extreme Performance

ISMI follows the same high standards used for springs supplied to U.S. government-contracted machine guns. These systems cycle at extreme speeds, so the springs must perform under constant stress. Additionally, the founder’s experience in Indy car racing research adds precision engineering and advanced performance to every spring design. This combination ensures unmatched strength and reliability.

Enhanced Pistol Performance

Installing an ISMI Hammer Spring / Mainspring improves your pistol’s hammer response. It reduces inconsistencies and enhances the overall feel of your trigger system. You can pair it with other premium ISMI small parts for a complete 1911 upgrade.

Key Benefits

• Long-lasting, stable tension

• Smooth, predictable hammer operation

• Durable, fatigue-resistant silicone chrome alloy

• High-performance engineering for demanding conditions

• Proven quality from government and motorsport applications

Whether you are upgrading for precision shooting, tactical reliability, or competition performance, the ISMI 1911 Hammer Spring / Mainspring – 15 Pounds ensures your 1911 performs with consistent power and control every time.