So I've played the game through 3 times now and each time I had a disgustingly overpowered gun. Each time I would have a short distance back up and also a sniper rifle but these became the main weapon and totally cut through everything. I think this is the main advantage of playing survival, you get some great drops. My brother is playing on normal and doesn't get these drops.
1) Legendary two shot assault gun, two projectiles so double the damage. 190 damage per shot.
2) Mini gun with 25 bleed damage per shot. Not kidding, this thing will kill an entire army. You can send a Legendary super mutant or deathclaw to hell in 2 secs.
3) Submachine gun with 15 exploding AOE damage. Super fast like a mini gun and the AOE means you can kill enemies bunched together. Great against ghouls, shoot them in the legs, even glowing ones go down super fast.
Only downside to weapons 2 and 3 is they eat up a lot of ammo so I can't use them constantly and expensive to maintain because of the ammo cost.
What's the best weapons you've had?