>it's called a "brush gun" because the larger caliber shoots through tree limbs better!
Umm, no, that's retarded. First of all, why are you shooting at animals without a clear sight line? The reason that brush guns are brush guns and shoot large bore and relatively slow moving bullets is because there's simply no need for high velocity or ballistic performance when you're limited to less than 100 yards. Thus it makes far more sense to fire a large projectile with better wounding capability that isn't dependent on velocity or expansion and won't ruin meat. Additionally, larger bores are more efficient, meaning the guns can be shorter and thus better suited to woodland hunting where the limited sight radius will not pose an issue.
This would've been common knowledge back in the days when everyone used muzzleloaders, but it seems with NFA laws people literally forgot what "Brush gun" meant due to being limited to 16" barrel on cartridge guns.
I dare say the "brush gun" meme is even more of an example of mass psychosis than the "scout rifle" concept.