rellascout
member
I'm guessing FN never went the Detective short slide route because of concerns about reliability and durability. When you have a reputation for making one of the world's most reliable service pistols, you'd have to think twice about altering the basic design. On the FM short slide guns, the recoil spring guide rod is different (as is the spring itself) and there seems to be a concern about recoil spring life.
I am not sure I agree with this line of thought. They certainly modified the design to accomidate the 40 S&W. People like C&S, the late great Behlert shortened BHPs without realiblity issues.