The Terrible Impetuosity: The Pennsylvania Reserves at Gettysburg, Jeffrey F. Sherry, Gettysburg Magazine, Issue Number 16, January 1997.
Excerpted text is found at the Pennsylvania Reserves Historical Society online.
The July 2 charge of the Pennsylvania Reserves from the north and west side of Little Round Top and into the Wheatfield was reenacted by the present day Pennsylvania Reserves Division, a Civil War Reenactment group. The event was May 22. The march was from the east slope of Powers' Hill to the stonewall on the northeast border of the Wheatfield. At the stonewall, the names of those killed were read aloud accompanied by a time of remembrance. Accompanying photos are by Civil War Librarian.
While marching to the left, Crawford received an order, presumably from Sykes, to send a brigade to aid the brigades of Col. Strong Vincent and Stephen Weed, which were heavily engaged on Little Round Top's southern and western slopes. Crawford ordered Fisher's Brigade, which was in the lead, to move left across the summit of the hill to Vincent's aid. Crawford then ordered Colonel Jackson's 11th Reserves, bringing up the rear of Fisher's column, to remain on the south slope of the hill, and McCandless' Brigade formed on Jackson's flanks and in his rear. Crawford's first line on the north slope, from right to left, consisted of the 6th Reserves under Lt. Col. Wellington H. Ent, Jackson's 11th Reserves, and Col. William C. Talley's 1st Reserves. The second line, close behind the first, consisted of Col. Charles F. Taylor's 13th Reserves (Bucktails) on the left and Lt. Col. George A. Woodward's 2nd Reserves on the right, all under McCandless' command.
As the brigade settled in among the rocks and stumps on the rugged slope of Little Round Top, the scene in the valley below them must have been a sight few would forget. The setting sun cast a dull reddish light on the smoke rising from the Wheatfield and nearby woods. Thousands of Federal soldiers from several divisions and corps retreated across the valley and some, Crawford reported, through his lines and down the Wheatfield road heading to the rear. Some came without weapons and with Confederate skirmishers close behind. At this point, an unidentified "Dutch Captain" who, according to Colonel Jackson, was an officer in Capt. Frank C. Gibbs' Company L, 1st Ohio Light Artillery, approached the colonel with a phrase that would become part of the lore of the Pennsylvania Reserves. Gibbs' battery held a position to the right of McCandless' line with two sections, while one section was higher up Little Round Top's north slope, just behind the right of the Bucktails. According to Capt. Henry N. Minnigh of the 1st Reserves, the "Dutch Captain...raved and swore, when it seemed as if his guns would be taken." "Dunder and blixen, don't let dem repels took mine batteries" shouted the officer to Colonel Jackson. Jackson told the man to "double-shot his guns, hold his position, and we would see to their safety." The men nearest to the artillery officer called out further comfort: "stand by your guns Dutchy, and we will stand by you."
The smoke and setting sun were making it difficult for McCandless' men to tell friend from foe. When Colonel Jackson asked two retreating Federal soldiers if their front was clear of friendly troops, one replied that the men behind them were "Johnnies." That was enough for the colonel, and he ordered his men to open fire on the advancing Confederates, just then beginning to scramble up the face of Little Round Top's northwest slope. Most accounts agree that McCandless' Brigade fired two volleys at close range into the advancing Confederates and Gibbs' guns poured in double canister as well.
While few of the Pennsylvania Reserves would admit to it later, they were not alone on Little Round Top's north slope that evening. The 98th Pennsylvania of Brig. Gen. Frank Wheaton's Sixth Corps Brigade had come up to the left rear of the 1st Reserves' line and charged down the slope into Plum Run Valley, obliquing to the left as they advanced with a "hurrah," stopping at the base of Devil's Den. Interestingly enough, the 98th's commander, Maj. John B. Kohler, did not even mention the Reserves presence or the advance they were about to make on his right moments later. Surely he could not have missed the advance of five regiments only a few hundred yards away. Kohler did not even mention the Fifth Corps in his report, believing the soldiers on his right were from the Second Corps.
At this point, General Crawford rode onto the stage. Seizing the flag of the I st Reserves, one of whose color-bearers had fallen, the mounted Crawford placed himself at the front of his line and shouted, "Forward, Reserves." Colonel Jackson of the 11th Reserves said it was he who ordered the charge. Nevertheless, forward they went down the slope with a loud cheer "peculiar to the Reserves," the color-bearer of the 1st Reserves trailing behind Crawford. The general's account had the man holding Crawford's stirrups and trouser leg all the way across the valley, but Crawford's version is the only one that includes this detail. The Confederates they charged into were about spent after fighting across the Wheatfield and through Rose's Woods to the west. The brigades of Brig. Gen. Joseph B. Kershaw, Brig. Gen. Paul J. Semmes, and Brig. Gen. William T. Wofford of Maj. Gen. Lafayette McLaws' Division and Brig. Gen. George T. Anderson's Brigade of Maj. Gen. John B. Hood's Division, both of Longstreet's corps, fell back as the Pennsylvanians advanced at the run down the rocky slope.
As the regiments under McCandless' command charged down the hill, the 2nd Reserves and the Bucktails, who together formed the second line, shifted to the left to come into line with the other Reserves regiments. For reasons never fully explained, McCandless' Brigade had come onto the field in reverse order. At the moment the advance was ordered, at least one regiment, the Bucktails, was trying to counter-march to get everyone where they were supposed to be. Had they advanced as they were, the rear rank would have been in front and all the officers, non-commissioned officers, and file closers would have been in the wrong place. They managed to get it all sorted out just as they advanced, but it no doubt caused a few tense moments as they went through complicated maneuvers under Confederate fire. 
As the Confederates fell back rapidly, they still inflicted casualties on the advancing Reserves. Lt. Col, Alanson E. Niles of the Bucktails fell at the base of Little Round Top with a bullet in his hip. The 2nd Reserves reported the loss of three color-bearers in the charge across what Colonel Jackson called "the swamp"-Plum Run. The men of the 98th Pennsylvania remembered that mud slowed and disorganized their advance .
As they approached a stone wall on the western edge of the little valley, the left of the Reserves' line began to take notice of heavy Confederate fire coming from the vicinity of Devil's Den, causing the left regiments to incline in that direction to confront it. This fire from Devil's Den would keep the Bucktails busy for some time to come. At the stone wall, the Confederates rallied briefly but were driven off after a short hand-to-hand fight. The historian of the 1st Reserves wrote later that cries of "Revenge for Reynolds" were heard and that the Confederates "could not stand against the terrible impetuosity of this charge, and at last broke and fled from the field."
Many of the Reserves' officers later wrote that they had trouble restraining their commands once they reached the stone wall. The Bucktails advanced over the wall and up the slope beyond and through the woods to the eastern edge of the Wheatfield until Colonel Taylor, realizing he was advancing without support, ordered everyone back to the stone wall that would be so prominent in official reports written after the battle and accounts written by veterans after the war. Confederate fire from the 1st Texas in Devil's Den had begun to wear away Taylor's left and would soon prove to be his undoing.
Full Text of Pennsylvania Reserves at Gettysburg by Jeff Sherry located at the Pennsylvania Reserve Historical Society online. For more information on Pennsylvania Reserve reenactors go to the Ninth Pennsylvania Reserves, Company A's website.