Wolves can be a bit unfortunate to run into if you've got low-level equipment, since they're "unicorn-lite". Ice elementals deal more damage than you'd expect them to and can be tricky to hit at times.
Still though, compared to the other biomes? No sweat at all.
Also, just did some mucking about. I've been trying out endgame bows to see if they match up to the shooty firearms, and... Well, the answer is still pretty much just "no", but it's nice to know the details of that.
The best bow in the game at this point is probably the Ice Bow, which can drop from ice mimics. It's got the highest arrow-launcher base damage in the game, and a not-unreasonable firerate.
As both an upside and a downside, it also converts all ammunition fired into "ice arrows". These are not the "frostburn arrows" that you can create out of an ice torch, since they don't inflict frostburn unless you're wearing the special Mr. Freeze suit. This means that while you can just skim by using only cheap wooden arrows, it also means that using any other, more damaging/tactical arrows is completely pointless and counterintuitive. Also, ice arrows can't be picked up after use, negating the normally 1/6 chance to get an arrow back after you've fired it.
Otherwise, we have the chlorophyte shotbow, which fires (on average) three shots per arrow. Again, you can't reclaim any of the arrows afterwards. Someone might think you could use this a bit like a shotgun and do lots of damage by hitting someone with all three shots, even though each individual shot does slightly less damage than one fired by the next tier down, the hallowed repeater.
And you'd be right, it does do a lot of damage... Provided you're using an arrow type where that actually works.
If you use any kind of piercing (jester, unholy, chlorophyte) or explosive (currently just hellfire, to my knowledge), then only ONE arrow per enemy will register. All the others will pass straight through (or in the case of the hellfire, they all blow up but only do the damage of one). Ichor arrows are probably your best bet for dealing mass damage, since they do a fair clip of base damage and also deal the irresistable ichor debuff. All depending on how the game calculates things, it might even go so far as to factor in the debuff of the first shot to hit before the other two connect, thus resulting in even more damage just in one shot (venom arrows do more base damage, but they have a more expensive component and the venom DoT doesn't really help your primary damage output all that much).
Holy arrows ALMOST become useful with this setup, since you wind up with a massive shower of piercing stars coming down, which means that on average for every one holy arrow you use you're actually generating 9 projectiles at a time (3 arrows, plus 2 stars per each arrow). Now, all these projectiles do bugger all for damage, but still... They're crafted in larger stacks than any other arrow except chlorophyte, and what else are you going to use unicorn horns for anyways? Useful or not, they are certainly very entertaining to use when dealing with a huddled group... Also, fantastic for exploring caves and such. Lights up practically the whole screen.
I'd like to try that setup with orichalcum armor, to see if it generates petals for all those projectiles. THEN we might be looking at some actual damage being dealt, especially to worm types.
Still though, as far as ranged weapons go? Guns have the real damage endgame. Sniper rifle is utterly unbeatable s far as damage-per-shot goes, as even someone without decent modifiers can get up to 275 normal damage in shroomite stealth, and a powerhouse critical is rarely far off. For more general usage the tactical shotgun is amazing, boasting damage, good rate of fire and great knockback (I've launched possessed armors offscreen with a good hit).
In regards to ammo efficiency however, I personally think that the clockwork rifle has a good shot at competing with the megashark. The clockwork has 4 less base damage from the launcher, but it is guaranteed to only use one round per three shots it fires (it also doesn't have the same bullet spread as the M*sharks), and then that one round only has an 80% chance of actually being used if you have ammo conservation armor on. While the rifle itself doesn't have knockback, the rounds it fires still do. Unfortunately, this DOES mean it can't get the unreal modifier, but it's still perfectly usable well into hardmode in my opinion. Especially since you can more readily use the higher-tier ammunition for it without having to worry about chewing through it too quickly.