With the creation of the Union Defence Force, in 1913 the Natal Carbineers formed into the 1st and 2nd Mounted Rifles (Natal Carbineers). 1935 redesignated as the Royal Natal Carbineers, and reorganised as two infantry battalions of the ACF. The 1st fought throughout WWII, becoming the Motor Battalion of the 11th SA Armoured Brigade (with quite a few Rhodesians serving with it).

The 2nd Royal Natal Carbineers were converted into the 14th Armoured Car Company, SA Tank Corps, amalgamating with the 13th Armoured Car Company, formed from the Imperial Light Horse, to form 6th Armoured Car Regiment, that was an outstanding unit in North African operations. Subsequently disbanded.

Post WWII remained a single infantry battalion, with the formation of the Republic in 1961, the Nationalist Government forced the now Natal Carbineers to remove the "crown" and replace it with a Batavian lion. Like other traditional regiments at that time, they managed to obtain permission to retain the "crown" in the centre of the badge.... which in heraldic terms is far more significant than being located at the top!