I agree Dave but in the first waves of landings it was machine gun a (and mortar) fire that caused the carnage. Most contemporary accounts concentrate on the devastating machine gun fire and complete absence of any cover.
Official Unit Report, Company A, 116th Infantry, 29th Division
"As the first men jumped, they crumpled and flopped into the water. Then order was lost. It seemed to the men that the only way to get ashore was to dive head first in and swim clear of the fire that was striking the boats. But, as they hit the water, their heavy equipment dragged them down and soon they were struggling to keep afloat. Some were hit in the water and wounded. Some drowned then and there... but some moved safely through the bullet fire to the sand and then, finding they could not hold there, went back in to the water and used it as cover, only their heads sticking out.
"Those who survived kept moving with the tide, sheltering at times behind underwater obstacles and in this way they finally made their landings. Within ten minutes of the ramps being lowered, Company A had become inert, leaderless and almost incapable of action. Every officer and Sergeant had been killed or wounded. It became a struggle for survival and rescue.
"The men in the water pushed wounded men ashore, and those who had reached the sands crawled back into the water pulling others to land to save them from drowning, in many cases only to see the rescued men wounded again or to be hit themselves. Within twenty minutes of striking the beach Company A had ceased to be an assault company and had become a forlorn little rescue party bent upon survival and saving lives."
This from a Royal Navy account,the RN provided many of the landing craft to the Americans and they were crewed by the RN.
"As we got nearer, shells were exploding in the water and as the ramp came down just short of the shoreline, machine gun fire cut them to pieces. Most of them never got more than a few yards from the ramp."
Bill Ryan of the 16th Infantry Regiment had a lucky escape.
"On the way towards the beach we lost two boats which were simply swamped by the high waves. The coxswains of the four remaining boats became disoriented; this was mainly due to the loss of the patrol boat which was supposed to ensure we were on the correct course for our assigned area. Also, the beach was covered in haze and smoke from the earlier heavy bombardment; this combination made identification of landmarks impossible.
As we neared shore the strong current forced our boats off course, taking us about two miles to the West. By the time we re-traced our proper course we saw that the two rifle companies which were supposed to land on our right flank at 'Easy Red' had actually landed on our beach which was identified as 'Fox Green'. Their landing craft had the beach fouled, so we were unable to land. After circling around off the beach like sitting ducks, we finally made our run in. By this time the Germans had the beach under heavy fire."
The artillery tended to target the landing craft. It was apprehension about the German artillery that caused the various landing craft to be launched from so far out,most were launched from about 10 miles off shore. This in turn led to further problems in the marginal conditions,not least that hardly a unit landed where it was supposed to.
Steve