One of the items in last weeks Brownell’s order was a 1911 Auto Checkered Mainspring Housing, part# 555-102-004WB, made by John Masen. I prefer an arched housing and the lack of available bright stainless or nickel is why I ordered it. This is a rough stainless part and I intended to polish out to match the nickel finish. I filed the exterior flats smooth, cleaned up the checkering and polished the works, which entailed about 2 ½ hours. The part didn’t finish out half bad.

My first inclination something was wrong, however, came when the mainspring cap wouldn’t enter the housing. This was fixed with a little deburring. When I discovered that the pin hole was drilled so far off that the mainspring housing pin wouldn’t enter the assembled part through the frame, I got pissed. To eliminate variables, I also tried it in an early 90’s Springfield 1911; same result. So I re-drilled the hole and eventually got the Rock Island assembled. It will do until I can find another replacement.

So now I have a no-account mainspring housing, with about three hours of work in it. It has been heavily modified so I don’t expect an exchange. I’ve been building 1911’s since the late 70’s and this is the first mainspring housing I’ve ever seen that wouldn’t assemble to a frame. It is easily the single worst frame part I’ve ever purchased, but it taught me a valuable lesson. ALWAYS try a part for fit, before finishing it. With everybody and his drunk uncle building 1911’s & aftermarket parts, you literally can’t take anything for granted.

I’m adding a few pics to illustrate the poor fit of the Masen mainspring housing. I actually took quite a bit off the bottom of it during the polishing process and it’s still poking too far out the bottom of the frame- and barely engaging the grip safety at the top. Do yourself a favor guys, and avoid Masen or ITM 1911 parts.

The Greider Precision Trigger, on the other hand, was great