150 Confederate guns pelted Union positions with up to 300 rounds per minute as Union crews fired back with approximately 100 of their own weapons.
The Civil War was a revolutionary conflict for the planet with steam power, repeating rifles, and improved cannons all changing the face of warfare. European powers sent observers to see how battles were fought, and how the rules of combat evolved as the conflict wore on.
A cannon sits on Powers Hill at Gettysburg National Military Park.
(National Park Service)
This changing industrial warfare led to butchery on a grand scale. There are a lot of ways to measure the war, but one of the greatest artillery exchanges of the war was an almost two-hour duel at Gettysburg, Pennsylvania, that, tragically for the Confederate infantrymen, immediately preceded Pickett's Charge but failed to dislodge the Union guns.
The exchange came on the morning of July 3, 1863. Two days earlier, on July 1, Confederate scouts had pushed against Union forces near the crossroads at the center of the small town of Gettysburg. Neither side's generals had chosen the ground, but they both reinforced their men in contact and stumbled into one of the most iconic and deadly battles of the war.
On July 2, Confederate Gen. Robert E. Lee attacked Union positions on hilltops near the city, attempting to push them off the high ground before more Union reinforcements arrived. Confederate troops were in Union territory, and the balance of power would shift against them more and more the longer the battle wore on.
Civil War reenactors play as Confederate artillery crews in 2008.
(Daniel Schwen, CC BY-SA 4.0)
The July 2 attacks were fierce, and Union forces suffered heavy losses and ran low on ammo in some positions. On Little Round Top, for example, Union forces barely survived by launching a bayonet charge down the hill after most of the men ran out of shot, leaving them vulnerable to a Confederate assault.
By July 3, it was clear that Lee's invasion of the north would have to either succeed on this day or likely fail altogether. The Union troops, on the other hand, despite some missteps, had improved their positions, and it would take great skill and a bit of luck to dislodge them.
Union forces under Maj. Gen. George Meade were arrayed on a series of ridges, and attackers were able to push Confederate troops out of a nearby field in the early hours of the morning. In a bid to re-seize the initiative and soften Union defenses in the early afternoon, Lee ordered a massive artillery bombardment of the Union troops, focused on Seminary and Cemetery ridges where he hoped to attack and pierce the lines.
The total number of guns on each side was similar. A Civil War Trust map of the artillery positions shows 126 Confederate guns and 128 Union guns covering the battlefield, with over 50 Union guns either on Cemetery Ridge or immediately adjacent to it. A HistoryNet count of the weapons engaged pegs it at 150 Confederate guns that took part against 75 Union guns.
When the afternoon artillery duel began, guns on each side began a disciplined but heavy bombardment of the opposing forces. For over 90 minutes, Confederate artillery tried to pick off Union guns and crews as the men ran back and forth from the caissons and ammo dumps to the guns to keep the rate of fire up. Good crews on either side could fire two rounds per minute. Thousands of rounds crisscrossed the field.
It's the largest artillery barrage ever in the western hemisphere. The Union leaders ordered many of their crews to cease fire in an attempt to fool the Confederates into thinking the Union cannon crews were broken.
If the Confederate bombardment were successful, it would create a temporary gap in the Union defenses, an area where battered riflemen and depleted artillery crews would be hard-pressed to hold the line while reinforcements were moved in.
Union artillery holds its position at the Battle of Gettysburg.
Lee prepared a massive infantry column, the core of the assault coming from Maj. Gen. George Pickett's 4,500-man division, with about 10,000 more men coming from other brigades, for an attack directly into the Union center. This would break the Army of the Potomac in half and force Union Maj. Gen. George C. Meade to withdraw or allow his men to be cut apart.
Despite the quiet Union guns, despite the massive infantry column, some of the Confederate generals still believed that the infantrymen could not possibly capture the hill. Lt. Gen. James Longstreet was one of the top detractors of the plan, respectfully telling Lee that he didn't think 15,000 men existed who could take the hill.
He would be proven right. The Union guns had been mostly sheltered by trees and fortifications during the exchange, and they survived the Confederate artillery attack in good order. Many of the guns on Cemetery Ridge were still in perfect order with ready crews manning them.
The 15,000 Confederate troops faced a march with .75 miles of open ground between the last spot of cover and the first Union defenses. For the entire distance, the Union cannon crews could hit them with balls and shot.
In what would become known as Pickett's Charge, the Confederates came anyway. The artillery shredded their lines, but still, the Confederates advanced. Units faltered and were slaughtered wholesale on the open field, but the Confederates were undeterred. Fences at the start and end of the march had to be climbed or dismantled under fire, but the Confederates came anyway.
Union troops who had suffered devastating losses the year before at the Battle of Fredericksburg were merciless as the Confederate troops fell, yelling "Fredericksburg" at the fallen.
The Confederate troops did make it into infantry range, once charging at Union lines from only 80 yards away, but Union troops behind stone walls, fallen timbers, or raised terrain slaughtered even these attackers.
In total, Union forces lost 1,500 soldiers. The Confederate losses are estimated to have been over 6,000. The day featured what was, by some measurements, the greatest artillery exchange in Western Hemisphere history. It was an easy contender, by most measures, as the top exchange of the Civil War.
But it had failed to carry the day, failed to achieve its objective.