Cossack Peoples wrote:Is a carbine just a sawn-off rifle
Well yes but also no.
Historically it just meant a longarm for cavalry/mounted infantry use. Generally this meant shorter and lighter but it some times just meant no bayonet mount and a side bar.
Today it generally means a short firearm that uses rifle ammunition, often a shorter barreled version of military rifle however it can mean any short and handy rifled weapon designed to be used with two hands that isn't an SMG(and in the US meets requirements to not be classed as an NFA item)