It would fit in a MCK EVO, and it would fit in a MCK Gen 1 Smith&Wesson specific model (if you remove the front flash can). It would look ridiculous, though, and would be very front heavy. Without support for the extra barrel length, I do not know what extra stress it would put on the lock up. Bottom line is that putting it in one of these would not be practical. Just get a 9mm FPC or response, if you want an accurate long barrel S&W rifle.