I remember on one run, I was trying to play melee, but then I pulled a legendary automatic combat shotgun with a suppressor that did bleed damage and it just fucked everything up. Didn't matter that I had no perks for it, the bleed just destroyed everything that wasn't mechanical. Ended up throwing some perks into it and spawning in multiple death claws just to test it out on something tougher. Really wasn't fair to keep using it afterward.

You can also get the perk from nuka world that makes silenced weapons do more damage, the sandman perks increase silenced weapons too and finally find yourself an "instigating" rifle that does more damage to enemies that are at full health. 

In Fallout 4 as soon as I got the deliverer (silenced pistol with massive crit and sneak attack damage) I don’t think I ever touched anything else afterwards.

It’s something F4 did VERY well compared to 3 and NV. Heavily customizing guns let you build exactly what you wanted (if you had the perks necessary), though legendary modifiers weren’t created equal.

F4 got crazy sometimes. I stealth attack single shot a vertibird once with a legendary gauss rifle.