Alt Hx #5: The artillery barrage succeeds

This WHATIF postulates what the engagement may have looked like if the Day 3 artillery barrage had gone as planned.

The July 3rd Confederate artillery barrage is probably one of the least known tactics of the battle — given that it was immediately followed by the disastrous Pickett’s Charge, yet it is also perhaps one of the most memorable. Lee had massed about 120 cannons along Seminary Ridge. He instructed their commander, MAJ Alexander, to target the copse of trees at the center of the Union line on Cemetery Hill.

Day 3 had dawned finding Lee heavily frustrated by his failures. Although LTG Heth’s men had carried the first day of the battle, it closed with the Union falling back on the easily defensible series of hills south of the city. Until late in the afternoon, Lee had been unaware of this terrain. His flank attacks on Day 2 had failed to dislodge Meade’s Army which was now consolidated and densely packed into a 3-mile perimeter.

The frustrated Lee had convinced himself that Meade would have heavily reinforced his flanks, at the expense of his center. Knowing that a single brigade had reached the Union line in the late afternoon of Day 2, Lee was convinced that a multi-division attack on that center could break the Union line. Lee cobbled together an attack force with Pickett’s fresh division in the lead and two (heavily depleted) divisions from Heth’s Corps in support. He had wanted to use Longstreet’s two other divisions, but Longstreet begged off noting their high casualty rates on Day 2.

So as the designated attack divisions assembled under the protection of the heavily wooded west slope of Seminary Ridge, MAJ Alexander was aligning his cannons. When they opened fire at about noon, it was the largest and longest artillery barrage even seen in the Western Hemisphere and would not be rivaled until World War I.

There was only one problem: the barrage was completely ineffective! It accomplished none of its intended effects! Union soldiers wrote letters after the battle detailing their amazement in seeing the shells fly over their heads and explode in the logistics area to the east. There were casualties, for sure. After the 3-day battle it is recorded that there were 3000 dead horses to be disposed of. Many, likely most, of these were as a result of the shells exploding over the reverse slope of the Cemetery Ridge. Meade even had to evacuate his HQ eastward as shells fell around the farm house below the cemetery that he was using. But the fighting men on the crest of the ridge were largely unaffected!

As the story goes, earlier in the spring of 1863 an accidental explosion all but destroyed the main Confederate Armory that produced the fuses for these shells. Contracts were quickly let for smaller facilities to begin manufacturing these fuses. Unfortunately, and unknowingly, the gunpowder supplied to these new facilities was of an inferior grade — it burned too slowly.

Exploding artillery shells were a relatively new addition to the armaments of the era. They greatly added to the destructive potential of well-aimed artillery. Of course, the standard ammunition was the solid cannon ball. To this was added a variety of shells known as canister and grapeshot. These were essentially large shotgun shells that were used against massed infantry formations at close-quarters. The newer exploding shells were designed to be used against these same infantry but as a greater distance.

Most of Alexander’s 100+ cannons were aimed at the copse of trees designated by Lee. Unbeknownst to him, they were the site of the Second Union Corps LTG Hancock’s HQ. Some of the guns were attempting silence the Union artillery to the south which still had the range to target Pickett’s men as they emerged from the tree line. Unfortunately, for Heth’s men, the position of Alexander’s cannon do not allow him a good range to the Union forces in the cemetery.

The Confederate artillerymen knew that something was wrong with their shells, but not exactly what. They had noted that they seemed to be over shooting their aiming points, but the reason was unclear. Up to this point in the battle, the artillery was largely firing at moving formations of men and so many adjustments to their aim were being made. On Day 3, however, they were firing en masse at a static target. Alexander had correctly estimated the range to that target and given instructions as to how to set the fuses. They contained a crude dial that set the number of seconds that the shell should fly before detonating over its target. All was correct, except for the slow-burning fuses which caused the shells to fly longer (farther) and detonate beyond the ridge.

Alexander’s problem was further aggravated by the black powder that was the propellant for these shells. It created a huge cloud of smoke around the cannons. Because they were in the trees, there was little breeze to clear the smoke. Once they began to fire, no one could see across the valley to assess the targeting. In short, Alexander had no idea that his shells were overshooting and therefore had no opportunity (nor reason) to change the fuse settings.

So far, I have described the facts of the actual barrage on Day 3. The WHATIF of this essay is how the Pickett’s charge may have gone differently if the shells had exploded where Alexander aimed them. Or even if a spotter had been placed outside of the immediate area of the cannons were the view was not obstructed by the black powder smoke. The copula of the Seminary would have provided a good vantage point for such a spotter to communicate with Alexander that his shells were flying too far.

The actual barrage lasted just over an hour. Many shells would have been fired before a messenger could have brought news to Alexander that he needed to shorten the fuse time to better aim the shells, but there would still have been time for that.

For their part, the Union forces — primarily Hancock’s Second Corps — were massed in depth behind the low stone wall that ran the length of Cemetery Ridge. As such, they were well protected from rifle fire and even somewhat from solid cannon shot, but they could have done nothing about shells exploding over their heads. Even though the shells were mostly over flying them, Hancock mounted his horse and rode up and down his line trying to calm his men.

Well-trained artillery crews of the day, could fire up to 5 shells a minute! Do the math! 120 cannons perhaps averaging even 3 shots per minute over an hour means that about 20,000 shots were fired! Most of them aimed at a small area of Cemetery Ridge.

Just as MG Buford’s opening barrage had sent the marching Rebels fleeing, it is highly likely that even Hancock would have been unable to keep his men in place as thousands of shells peppered them with shrapnel. No sane person would lie there and await death. Most of his corps would likely have broken and run to the rear to avoid their death. A hole, dozens of yards wide, would likely have opened around that copse of trees. If he had stayed, Hancock, himself, would likely have been hit!

After the barrage ceased, Longstreet ordered Pickett to advance along with the supporting divisions on his left. It took Pickett about 20 minutes to traverse the one mile from one ridge to the other, but in the actual battle he was under intense artillery fire the entire time. If that Union artillery had been largely silenced, or destroyed, he would likely have advanced somewhat faster. We know for a fact that the Union forces located in the Cemetery were able to keep Heth’s two divisions pinned down and to keep them from supporting Pickett. So Pickett’s division was still alone in making the attack.

Any attempt by the Union commanders to gain control of their men and fill the gap would likely have taken longer that Pickett’s transit time. Even those Union units to the north and the south of Hancock would have been slow to react by moving to fill the gap and thereby weakening their own defensive line.

Since this as a ‘hasty attack’, Pickett was not able to bring artillery with him — his attack was purely by infantry. But we know that some of the Rebels who actually passed beyond the wall had captured a few Union cannons and were in the process of turning them when they were all gunned down. We would expect that having successfully penetrated the Union defensive line as least a few surviving Union cannons would have been captured and used against them.

History does not record whether Pickett’s three brigade commanders had an actual plan for how they would exploit a successful breach of the wall. Might Garner and Kemper have turned north and south and attacked adjacent units? That would have left Armistead to push his brigade over the ridge and into the Union rear area. Pickett had a total of about 5000 infantry, but they would have been fighting at least an equal number of (shell-shocked) Union infantry.

Meade had the distinct advantage of having a closely-packed defensive line spread over barely 3 miles in a fish-hook pattern. It wouldn’t have taken long for him to shift reinforcements into the area under attack. He even had the entire Sixth Corps in reserve just a short distance to the southeast.

In short, given that Pickett was alone (without support to his left or right), it is highly unlikely that a successful breach of the Union line could have been exploited into anything more. Lee simply had no other troops available to exploit the broken line. Meade would certainly been able to react and suppress the invasion of his defensive line. Pickett would have had to attempt to withdraw over the same territory he had just crossed. It is highly likely that huge numbers of his men would have been captured in addition to the casualties he sustained.

It is not imaginable as to what Lee had expected would be the outcome of a ‘successful’ attack by Pickett. What precisely were Garner, Kemper and Armistead planning to do when and if they breached the wall? 5000 versus 70,000 infantry are horrendous odds. The Confederates would soon have run out of ammunition whereas the Union soldiers would have had a plentiful supply.

In short, even under the best of circumstances, given what Lee had to throw into battle on Day 3, it would seem that his plan was doomed to fail even if it ‘succeeded’!