STI was the first one to come out with a wide body polymer frame for the M-1911 (I can be corrected on that, but that's what I know, at the moment). Their frame is unique, in the sense that it comprises of two parts, an upper steel section, on which the slide is attached, and a lower hi-tech plastic grip section. The two sections are attached together at two points, one above the front part of the trigger guard and another where the top grip screw is located. Since the STI frame does not use separate grip panels, this screw is only used to keep the two frame parts together. The lower grip screw is there only for appearance reasons.

STI's frame kit includes the frame (both parts of course), the trigger, the mainspring housing and the magazine release button assembly. They are also marketing a separate "Completion Kit" as they call it, which includes all the parts necessary to build a complete lower half of an M-1911.

I am in the process of obtaining an STI frame (waiting for the Police to approve it), so you can expect to find here, in the future, more details about the frame and the process of building a high capacity M-1911.

In the picture below, you can see a comparison between the grip width of a standard, single stack M-1911 and the STI's one.

My only question is, why a frame with a rectangular trigger guard? It can not be used with any of the normal holsters. Come on folks, do not make our life difficult with things that almost nobody is using anymore! I plan to have the trigger guard, on my frame, rounded to a more conventional shape, althought I think that the wide dust cover will not allow the gun to be used with any of my holsters, anyway.