Well this is a good start for your attempt at a war story. You got the date, times and units right, the delay caused by poor navigation and you describe the carnage of war well. You might want to read a little about Ranger operations. I think that this would give a better focus to your attempt:
http://www-cgsc.army.mil/carl/resour.../King/King.asp
I think that it is rather cliché to show bewildered recruits facing the horrors of war for the first time. If one were to write that a group of Viking berserkers had faces full of fear or were led by green leaders, it would of course sound quite strange. Rangers were elite troops. The men in the Ranger units were actually wounded by gunfire and shrapnel or even died while still in very realistic training. They were hand picked soldiers from a group that had volunteered to fight with the very best. Their officers were also highly motivated. Many had experienced combat. So have your characters reflect this. The only fear that an elite soldier has is the fear of failure, of valiant effort wasted.
Now for the small stuff. You have several typos that you should clean up which is not a real problem. Also, you correctly state that the Texas had 14-inch guns, but then mention that 16-inch guns are fired. I have a comment about the pace of your story. The lines where you have the time, location and date unnecessarily break the suspense or tension of the combat you describe. We know that the story is about D-Day at Pointe du Hoc. Keep the action going. Finally, the Ranger falling off the cliff clasping his breast and saying “Good-bye all!”, has to go. Shakespeare was not a Ranger.
Good luck!
“Rangers lead the way!”