On the first day of the Battle of Gettysburg, July 1, 1863, Burns took up his flintlock musket and powder horn and walked out to the scene of the fighting that morning. He encountered a wounded Union soldier and asked if he could use his more modern rifle; the soldier agreed and Burns moved on with the rifle and with cartridges in his pocket. Approaching Major Thomas Chamberlin of the 150th Pennsylvania Infantry, Burns requested that he be allowed to fall in with the regiment. Chamberlin later wrote of Burns moving with deliberate step, carrying his Enfield rifle at a trail. His somewhat peculiar dress "consisted of dark trousers and a waistcoat, a blue 'swallow tail' coat with burnished brass buttons, such as used to be affected by well-to-do gentlemen of the old school about 40 years ago