On May 14, 1863, Battery E &amp; G, 1st U.S. Artillery was transferred to the Captain John C. Tidball's Second Brigade of the Horse Artillery. Its four light 12-pounder Napoleons were traded-in for four 3-inch Ordnance Rifles. The battery re-trained as a "flying artillery" horse artillery company until June 13, when it joined Brigadier General David McMurtrie Gregg's Second Division of the Army of the Potomac's Cavalry Corps. Attached to Federal cavalry in pursuit of the Confederates moving northward toward Pennsylvania (eventually to Gettysburg, Pennsylvania), Randol's battery was constantly in battle, and learned to fight like horse artillerymen utilizing rifled guns on the front line of battle rather than placed toward the rear and supported by infantry as they had been previously: We were frequently on the skirmish line, and sometimes in advance of it, and drove the enemy's batteries and cavalry from all their positions as fast as selected, dismounting some of his guns, blowing up limbers and caissons, and killing many men and horses. The accuracy of fire of the rifles, their long range, and the ease with which they could be handled, gave us a confidence in them which was not shaken during the remainder of the war.Battery E &amp; G was engaged in battle at the Battles of Aldie, Middleburgh, and Upperville, moving with the Cavalry Corps to pursue raiding Confederate Cavalry under Major General J. E. B. Stuart's cavalry when the Battle of Gettysburg began. It received orders to proceed directly to the Gettysburg battlefield, where it arrived July 2 (the second day of battle) and occupied a position to the right of the Union line. On July 3, while the main action at Gettysburg was focused upon the Union center at Cemetery Ridge, Randol's battery was engaged with the Cavalry Corps against Stuart's rebel cavalry attempting to flank the Union right several miles to the east. The Confederate cavalry was successfully repulsed.