I find it tends to vary based on a combination of Armor and your survivor’s condition going into the fight. Weapon’s mostly irrelevant; I’ve had day 1 survivors take Moose down with nothing more than a burning bush and his bare hands. On the other hand, I’ve also had firearm-wielding survivors get completely mauled because of a ninja moose jumping out from behind a building/tree.
What I’ve found makes moose so deadly is that they:
A) Are really bloody fast. At 200 speed, they’re getting two hits in to the typical survivor’s one, and once one gets you in its sights, you usually can’t run from it (in comparison, Feral Predators, the fastest zombie in the game, only have 140).
B) Inflict a metric crapton of pain on a hit (which they get two or more of each turn), which tends to trigger a death spiral.
C) Might be anecdotal, but I’ve found they’re really good at landing headshots. Most limbs are easy enough to get a few layers of clothing on and thus have some protection, but finding a good helmet is a little trickier.
Ultimately, fighting moose comes down to using the environment to your advantage, and praying you’re in good condition when the fight starts (speed reduction will kill you every single time against a moose). Fire reduces their morale (improving your chances, since they’re more likely to back off when injured), so lighting things up is usually a good strategy. Killing it without letting it close is also a good strategy, and one lucky break is that moose can’t actually bash anything, so running into a building and shutting the door behind you also works wonders for escaping.
