I reckon the whole point of the two bullet aspect of the story the same as there being ammo for different weapons in the bunker, but no weapons.
If the Father had plentiful ammunition, or any resources at all, really, the story would have indeed had a pile of bodies. It's good to have at least one post apocalyptic story that doesn't have unending shoot outs. Even The Road Warrior had Mel bluffing a good portion of the movie as to the rounds in his sawed off. It's a plot device to move the story in a different direction. I've read quite a few EXCELLENT views in the underused Movie and Home Theater Forum, as well as the Survival Forum. There are some smart fuckers on this site, and the logical arguments are compelling.
I believe the best reply written explained the likelihood that no matter how many weapons you have, some will be lost fleeing, some will not have available parts for repair, some may even need to be sacrificed as barter for medical supplies or food.
What I believe may be a large part of the negativity felt towards this film and book stems from what it represents to the members of this board. The idea that regardless of prep, in a bad enough situation, far enough along, survival percentages drop to near zero. It's heartening to me, though, the amount of people who don't like this film. It just means that there's a large of amount of folks here who can't stomach a situation that they can't grit their way through, that when observing a situation where it's that far gone, and suicide is a VERY real option, most of you say "Fuck this, NEVER!!" You guys have a good attitude.
I love the book, by the way. Sorry. How the hell do you have any hope when humanity is all but dead? How does a man go on, if not only for the sake of his child? Powerful stuff.