Ed Brown Products Recoil Spring 1911 .45 ACP 18lb Commander Steel. When you have the proper weight recoil spring for a particular load ejected brass should land 8-12 feet away. If brass is falling within a few feet of you your spring is too heavy for that load. If brass lands more than about 12 feet away your spring is too light for that load. Either case leads to reduced reliability. We recommend replacing the recoil spring every 3000 rounds. Ed Brown 5in 45 ACP Government models are equipped with an 16.5lb recoil spring as standard (our part number 9165-G) while the 18lb recoil spring (our part number 918-G) is generally preferred for heavier loads. Ed Brown 4.25in 45 ACP Commander models are equipped with a 20lb recoil spring (our part number 920-C). Specifications for Ed Brown Products 1911 Recoil Spring: Manufacturer: Ed Brown Products Color: Steel Gun Make: Ed Brown Package Contents: Ed Brown Products 1911 Recoil Spring What firearm models does the manufacturer say Ed Brown Products 1911 Recoil Spring is compatible with? The manufacturer suggests that Ed Brown Products 1911 Recoil Spring is compatible with Colt 1911 Government 5in Colt 1911 Commander 4.25inEd Brown Products 918-C: Recoil Spring 1911 .45 ACP 18lb Commander Steel