Ok boys and girls, a ranger grave is basically a small hasty fighting position for one individual to lay prone in. Here are two photos of them (first is just training).       Normally when you are digging a full fighting position you dig two ranger graves side-by-side and then connect the two with a larger section that you can stand up in. This larger section normally contains the water and grenade sump. I understand that digging into the map may not be a possibility, however, the majority of fighting positions begin with removing a thin layer of dirt and piling it up in front of you. This is called a perapet. Here is a picture of how the soviets did their hasty fighting positions:

      Here is one more picture from the US as well:
    These would be extremely useful for later in the game when FOBs are more difficult to construct. In real life a squad trying to hold an objective would form a perimeter and if they had time try to harden their position as much as possible with hasty fighting positions like this until a larger unit can come and help them. It should of course take a while to dig as to keep them from poping up everywhere but it would be nice to have.    EDIT: I may have missed mentioning this, but I believe this should be restricted to 50 meters within the rally position. So YES a squad can harden their position slightly, but then you absolutely know that is where their rally is.  AND these should be dug without the squad leader using build points or anything, the only restriction should be that they are in the range of the rally.    EDIT2: Maybe I wasn't clear enough, I know digging is not a possibility due to coding issues. There may not be any negative removal of dirt from the ground but a parapet would still be a possibility in a horseshoe shape around the individual.