Iver Johnson Arms Iver Johnson Mainspring Housing .45acp Blued Steel. After spending hours of research and interviewing I heard from countless people that mainspring housings are a common problem in 1911 pistols. Iver Johnson set out to solve this problem. The mainspring housing is one part of the problem. Every time you try to make one you end up making several modifications. At Iver Johnson Arms we try to find solutions to fix these problems. Whether you're fighting a corrosive abrasion or you're fighting to get a simple fix for a rusty or leaking mainspring housing we're here to help The Iver Johnson 1911 Mainspring Housing is one of the few that doesn't require any gunsmithing to install. It is easily installed and does not require modification to your pistol frame. This makes it a great replacement for a bad or old mainspring housing. Specifications for Iver Johnson Arms Iver Johnson 1911 Mainspring Housing .45acp Blued Steel: Manufacturer: Iver Johnson Arms Finish: Black Oxide Fabric/Material: Steel Gun Model: 1911 .45 ACP Dimensions: 2.30 X 2.30 X 5.85 in Length: 5.85 in Width: 2.3 in Package Contents: Iver Johnson Arms Iver Johnson 1911 Mainspring Housing .45acp Blued Steel What firearm models does the manufacturer say Iver Johnson Arms Iver Johnson 1911 Mainspring Housing .45acp Blued Steel is compatible with? The manufacturer suggests that Iver Johnson Arms Iver Johnson 1911 Mainspring Housing .45acp Blued Steel is compatible with 1911 .45 ACP