Oh, Goblin of Chaos...
You've obviously never seen a group of poachers in Africa mow down an elephant herd using FN FALs....
Oddly, the same 7.62mm jacketed round which will generally stop a human in a single shot will also drop an elephant in a single shot. I'm no talking about aimed fire here either... semi-automatic or burst fire and down they go like a house of cards. Quite horrid to watch, but educational, in terms of the vulernability of larger creatures.
The truth is, some humans pumped up on adrenalin, have been capable of taking many wounds before succumbing. The truth also is un-pumped humans have died form a single .22 rimfire. I guess the same applies to larger creatures, and herbivores and such are more likely to succumb to damage easily. Most of the 'incredible animal endurance' stories I've heard involve wild boars (7 .357 magnum shots and 3 from the M-14 to drop one), grizzly bears (if you don't kill him, you'll just make him angry), polar bears, or big cats.
At any rate, that's digressing. Your comment about AHL is correct.
AHL, Snapshot, Striker - they all allow you to play on a bigger canvas, thus the details get lost (of necessity). But try to resolve a platoon on platoon action in standard rules... oh.. my ... lord....
RPG rules aren't really meant to 'usefully' handle bigger fights. For those of us that like miniatures, AHL, snapshot, striker, At Close Quarters - all of these offer ways to fight these larger fights manageably. If you want to give characters some bonuses, you'll have to work them in yourself.