The term "Carbine" is entirely generic and really needs to be defined in context of the particular make, model & era of the underlying rifle. Excellent example, the German carbine: "Kar 88" with a bit less than 18" barrel. The World War I "Kar 98" a bit less than 24" barrel! Different strokes for same folks! I am here speaking of nomenclature just as actually applied to subject rifles!
To seek a component irrespective of specific 'genre', as to seek a mate irrespective of specific 'gender'... Hazardous 'fit'!
Be careful what you wish for... Lest you get it!
Best!
John