I am replacing a stock Kimber mainspring housing with a stainless S&A arched housing and noticed a pretty big gap between the frame and the housing.
I thought the frame might have been bent but measuring it proved otherwise, the housing is actually the culprit. The housing is tapered slightly front to back which leaves a gap, about .01 as seen above (notice the rail on top). Is this normal? Was the S&A housing designed to be a drop-in part with a lot of room for error? Anyone know a good housing to use with a tighter fit or possibly one that can be trimmed to fit?

I thought the frame might have been bent but measuring it proved otherwise, the housing is actually the culprit. The housing is tapered slightly front to back which leaves a gap, about .01 as seen above (notice the rail on top). Is this normal? Was the S&A housing designed to be a drop-in part with a lot of room for error? Anyone know a good housing to use with a tighter fit or possibly one that can be trimmed to fit?