[BanazirGalbasi]

Actually, shooting jackets (for high-power shooting, at least) tend to fit pretty tight. The idea is that they help hold your body more rigid, giving you better stability when shooting at longer ranges (200, 300, and 600 yards). While I agree that sport coats aren't fit the same way, the lack of mobility is pretty common.

[throwaway0a5e]

Sport coats are descended from the kind of thing well to do Europeans wore wear while shooting clays, riding horses, shooting at foxes while riding on horses, saying nasty things about the slavs, or whatever else well to do Europeans a century ago did for recreation. They aren't descended from shooting specific gear.