Armstrong's service record included the following • 1776–1781,
8th North Carolina Regiment, Captain in the
New Bern District Minutemen, then
Pitt County Regiment of the North Carolina militia • November 26, 1776, Commissioned a Colonel • June 1, 1778, commander of
4th North Carolina Regiment • June 20, 1779, wounded at the
Battle of Stono Ferry in South Carolina • January 1781, retired on half pay • 1781, appointed Brig. Gen. (Pro Tempore) for very short while when the NC General Assembly thought (incorrectly) that BG
William Caswell had resigned. ==Post war years==