Hello. The FM is a licensed copy of the FN Hi Power. I've not shot the Detective, but have fired several rounds in some of the full-sized FMs. They worked OK. Current FMs don't appear to have the lightening cuts on the front of the slide. Generally, the finish is not as nice as on the FN.
Richard, a frequent poster here, is kind of a "specialist" in FMs. I'm sure he'll have more useful information.
Best.