The 5th North Carolina was not combined with another regiment, but maintained its identity for four years.
Following the Battle of Williamsburg, the War Department assembled regiments from the same state into new brigades whenever possible. Brig. Gen. Garland's was one of several new brigades thus created. This brigade included the 5th North Carolina and three other North Carolina regiments.
John W. Birch has a service record with the 5th North Carolina Regiment which should include a remark showing that he was either killed or mortally wounded at Gaines Mill, Va., June 27, 1862. Please reply if you're interested in a copy; this is a service offered by the message board.