Ensure absolute reliability with full-power ammunition in your 1911 Government model with the ISMI 18 lb. flat wire recoil spring. This is our heavy-duty option, engineered specifically for shooters who use +P defensive loads or powerful factory ammunition. The advanced flat wire design provides a uniquely smooth compression feel while offering the strength needed to protect your firearm from excessive wear.

The ISMI Advantage: Flat Wire Technology

ISMI's flat wire recoil springs offer a distinct performance advantage over traditional round wire springs, making them a favorite of custom builders and serious shooters.

• Smoother Recoil Impulse: The flat wire design compresses more linearly than round wire, resulting in a smoother, less "snappy" felt recoil that helps keep your sights on target during rapid fire.
• Exceptional Durability: Crafted from certified aerospace-spec chrome silicon alloy steel, these flat wire springs are rated for an incredible service life, resisting wear and taking a "set" far longer than any music wire spring.
• Made in the USA: Proudly manufactured in the United States by ISMI, the top choice for high-performance firearm springs in nearly every shooting discipline.

Application & Tuning Guide

An 18 lb. recoil spring is heavier than the factory standard (16 lbs.) for a 5" Government model 1911. This makes it a specialized spring for specific, high-power applications:

• +P & High-Pressure Ammunition: This is the ideal spring weight for reliably cycling +P and other over-pressure defensive loads. It provides the necessary resistance to slow the slide velocity, preventing frame battering and ensuring longevity.
• Duty & Self-Defense Use: For a firearm dedicated to defensive use with full-power ammunition, an 18 lb. spring ensures a positive and authoritative return-to-battery, a critical factor for reliability under stress.
• Suppressor Use: When running a suppressor, which can increase slide velocity, an 18 lb. spring helps to manage the system's dynamics and ensure proper function.

Technical Specifications