In a low-angle shot from a car trunk, Earl holds his open palm directly behind the slide of his Beretta as he prepares to fire. Firing a Beretta or any recoil-operated pistol like this would severely injure his hand when the slide snaps backward.
In the final chase sequence, Jeff attempts to shoot out Red Barr's truck tires. After a few shots, a click is heard from the pistol and Jeff tells his wife he is out of bullets. A pistol does not just make a click when it is out of ammunition. If Jeff was out of bullets the slide on the pistol would automatically lock back, confirming all rounds were fired.
If Red's gang had been obliged to be awake and on the road for nearly 24 hours straight ("We need to get far away from this area and dispose of all our incriminating evidence! I don't care if that means that we DO have to drive all night to get back to my house!"), they would have looked exhausted and baggy-eyed; they could not have appeared fresh and vigorous the way they do while having an early breakfast at Red's house.