The snipers in Gunfire Reborn share different playstyles.
Piercing flame:
Aggressive, high firerate, ok damage, but overall, best for beginners.
Goshawk:
Passive, high damage, slow firerate (charge), not recommended for those who just want to jump in and gun everyone down as fast as possible, but it's a really strong gun if you have patience, and know how to use it. (Why do people hate on it? It's stronger than Piercing Sheet by miles.)
Golden Bow and Strike Wing:
Aggressive, High Firerate, Good damage, really fun to run, but not optimal if you're not good with projectile timing, at least at long range with the Golden Bow. The strike wing is just busted as of writing...
Bloody Drill:
Personal favorite. High dmg, slow firerate, bleed effect, a mixture between Piercing flame's firerate and goshawks damage, the drill is one of best middle ground snipers, but if you don't like the slow firerate, well, stick with the flame.
Double Caliber:
High Damage, High firerate, but crippled, kinda. The double shot feature of this sniper is a great idea. But the unique effect sucks... Half the times the effect won't even proc, making you waste bullets for 0 reasons.
Woodpecker:
Low damage, High firerate, rather unique n fun to use, not a fan of it, but It does decently well compared to... Well, Sting...
Sting:
Low dmg, wonky firerate, neat unique ability, but just... I can't like this thing. Maybe you can, I won't bash you down. But it's, so, awkward. And reloads slower than a freaking drill.
If i missed one or 2 i will re-edit this.

2 Characets, out of currently 4, are viable for sniping. (Dog can snipe but that's mostly meme build, not viable. Bird is just not even worth it. IF you proclaim that you can do some high damage with sniper on bird, you're either min-maxing or lying.) Depending on your skill level, and play style, you will choose either Cat (Crowned Prince) or Tiger (Lei Luo?)
Crowned Prince:
If you're starting out on sniping, or aren't consistent with aim, Prince is your best friend.
Advantages:

• Orb, freezing enemies in place helps with headshotting
  
• Elemental snipers can be boosted to do absurd damage (managed to get 497k out of a piercing flame)
  
• Smoke nades slow enemies down
  
• High survivability
  
• Energy Blade boosting your damage of snipers upon using the orb
  
• Generally viable to use any sidearm.

Disadvantages:

• Without an element, your damage might be low, or underwhelming.
  
• Certain snipers (Goshawk and Drill) might under perform without specific Ascensions or Inscriptions.
  
• Other weapons can outperform your snipers with ease (Miasma spam as example)
  
• Decently RNG orientated (Requires certain stuff to make them do serious damage. By serious i mean 20k+, which to me is weak but eh.)

Strategy and such will be explained later.
Tiger (whatever the hell he's called i always forget)
If your aim is consistent enough, or you played Zer0 (borderlands 2) a lot in past, Tiger is your friend!
Advantages:

• Makes any sniper do serious business
  
• Doesn't require much of a "build" (who the hell thought calling ascension choices "builds" ??? It's not an RPG for God's sake)
  
• Can rely without side weapons (Tho argus is always fine to have, staggers enemies n has knockback)
  
• (nearly) Any ascension you take can only make you do more damage with snipers
  
• Can be defensive and stay in back, or aggressive and go face first into enemy line (Depends on your ascensions n scrolls tho. Yes yes i know, everyone can do that. But having high dmg n resistance is something cat lacks most of the times.)
  
• Melee Zer0 Dream (i did a melee zer0 style run with the minecraft sword and oh my God it's amazing.)
  
• Consistent aim is heavily rewarded (ESPECIALLY WITH MAGICAL SUPPLY)

Disadvantages:

• Glass cannon (he has no health n shield, you can breathe on him and out comes a souffle.)
  
• Chain lightning has a % chance to trigger shock effect (honestly, i like that. It's a utility not a freaking, Thermonuclear weapon like cat can make it be)
  
• Hard to recover from stronger hits (Especially dmg over time/DOT)
  
• After getting revived you can die easily (You have ~20 hp, what the hell do you expect?)
  
• Unable to revive without going down instantly after reviving your teammate(s) (I mean this applies to Glass cannon factor, either way...)

Cat:
You're able to shut down any enemy with ease, to concentrate on hard hitters or just pain in the rear enemies (COUGH, Corrupt monk).
Use your orb on tanky enemies and try to target enemies who hit hard, or are near you.
Tiger:
You have no way to stop enemies, but your high damage can delete the weaker ones, and even the tanks. You should always target the hard hitters, due to your health and shield being as thin as paper. Enemies nearby can be hit with chain lightning for some damage, so you can finish them off later.
Main targets:
Chapter 1:
Longbow man - Homing, high dmg, annoyance, just overall irritating.
Spearman - They can hit hard, but they mostly will miss...
Horse Heads - If you don't have piercing, you're screwed. Get near them and dash back, they will try to melee you.
Chapter 2:
... uh, the, KFC Chickens with homing projectiles, whatever they are called. - These guys will catch you off guard so often, you'd want to deep fry them. Hide behind cover, or shoot them on sight.
Arsonists - Scary dinguses, can do a lot of dmg if you're not careful. But they're slow n tank, so, your choice.
Shotgun lizard, things. - STAY, AWAY, FROM THEM. ESPECIALLY IF YOU'RE TIGER. They can 1 shot you up close as Tiger.
Dark Faced bandits - Let them charge, Orb/Thunder Strike them from back, and kill them.
Worms - Always shoot them as soon as you see them.
Chapter 3:
Kappas - They aren't that bad, but can sometimes just, slow you down n you'll get barraged.
Octopuses - This is the most annoying enemy in the game, imo. Hide, or, target. Preferably target.
Lobsters - Long distance sniping with those, things they shoot, can hurt you, but otherwise not that annoying.
Corrupt monk - TARGET THEM INSTANTLY. NO SECOND THOUGHT.
Nihilant monk - Learn the pattern they sway while playing the flute, and/or dash away from them.
Sharks - Honestly, dodging their hooks isn't hard, just learn when (sound) and you're clean.

I won't mention every (cause i don't remember every elite...)
Chapter 1:
Horsehead - Pretty simple if you got piercing. If not, same as normal horseheads, touch shield, move away. And ofc kill the rest of his minions.
Beetle - boring, shoot, ded.
The one with speen mode - Keep distancing, freeze him, and ofc smoke em.
Lu Wu - Keep distance, just. Nothing special.
Stone Golem - Keep firing at his crit spot as much as you can, easily accessible, also use foundry, or secondary on the flying boulder things.
Chapter 2:
Coyote - haha you won't even find it. jokes aside, nothing unusual, shoot until it dies.
Lizard: Try to learn his "patterns" and dodge his attacks as much as you can. Also kill the enemies around.
Arsonist: Social Distancing 101. Nothng else to say.
Hench man? ... The guy with big ole shield. - Piercing? Saved. No piercing? Orb and get near him, fire off 1 - 2 shots n back up.
The fox, thing. - Easiest of them all, don't worry much about him...
Itchy - His beam isn't as deadly to cat as it is to Tiger, but you should still dodge it, you can get some crack shots off tho.
Flying thing - Don't get stuck in the holes, otherwise, not that hard to kill.
Chapter 3:
Monk (normal) - Freeze him often, and stay away. Just like nihilant monks.
Nihilant monk - I barely even witness his attacks, so uh. GLHF (Seriously, he's so weak)
Kappa - Lag machine. Hate him. Not that annoying, nor hard, just try to not get his shield fully up.
Lobster - Freeze, shoot, repeat, dodge...
Yaksha - Stay away from him, freeze him, and social distance 101. You'll regret hugging him.
Boat? a joke.

Chapter 1:
Horsehead - Same as cat, touch shield n you get a free headshot, or if you got piercing, ez pz.
Beetle - Spam your primary. This boss is boring...
SPEEN axe - Do not let him get near you, you will regret it.
Lu Wu - You know already, it's an easy boss.
Stone golem - Shoot his crit spot every time you get your primary recharged, and use your chain lightning on the flying boulders.
Chapter 2:
Coyote: Pretty weak, nothing special to say.
Lizard: For love of God do not get gang banged by the lizards. They will screw you over. Clean them and then take the boss out.
Arsonist - Not that hard, honestly, just kill the KFC Chickens... Mostly so you can stay away from the elite.
Shield men - It's a bit complicated, but in some way, not really. You'd preferably want him to shoot you, instead of getting near him, since he can 1 shot you.
The fox thing - Do i really need to tell you?
Itchyosaurus thing - Dodging the beam is your #1 priority, shooting him during beam phase can be risky.
Flying, thing...? - Annoyance and a pushover, hope you don't have ostrich rider. But generally, always on move, shoot him from time to time.
Chapter 3:
Monk - He can melt you. No seriously, he can melt you. Dispatch him fast.
Nihilant monk - i never saw him hit me so i really can't talk about him...
Yaksha - Back pedal, target him more than the rest, and y'know the rest...
Lobster - Honestly, there's no strategy for him either.
Boat - again, not a big deal.

Cat:
Don't be afraid to go in, you can do good even up close, except if you're low on hp.
Sharing is caring, never be greedy n mark guns you think would benefit others, and ofc, give others scrolls.
Tiger:
I'd say don't go face into enemy line, especially if you don't have good resistance.
Share your gear with others, don't be a greedy nugget.

My hands hurt from typing...
Jokes aside, thank you for reading, if you need help, post your comments here, I'll (try to) respond as soon as possible!
-Hobo