I'm at level 24 and have had pretty much the same weapon line-up throughout, with a few mods here and there. Only one of them is legendary. And no big guns, too heavy. I have 71 ballistic damage resistance, 52 energy DR, and lots of stimpaks and healthy food, and I rarely need to use power armor during combat. I'm not much of a stealth shooter. Only use stealth for the sneak attack bonus.
10mm pistol -- uses very few AP, great for building up critical meter, modded to 31 damage (66 fire rate, 34 damage per second); can single-handedly take out average raiders, mutants, animals by itself in VATS, even legendary enemies if Dogmeat holds him still and/or I use critical strikes.
Pipe automatic rifle, .38 bullets-- 127 fire rate, modded and perked to 25 damage = 53 damage per second. Modded to superior recoil, short scope (which gives 88 accuracy), and 191 range. Almost like a snipe rifle, but can fire repeatedly. Only 24 rounds per clip though. Crappy for VATS, since it uses lots of AP. Great for real-time, medium-range shoot-out. Modded to great hip-fire accuracy as well for close combat.
Automatic combat rifle, .45 bullets -- modded and perked to 35 damage, 90 fire rate = 53 damage per second. I use this interchangeably with the one above. I switch to this when .38 ammo is low, and vice versa.
Pipe bolt-action snipe rifle -- modded to 55 damage, 112 accuracy, and 215 range. Good for one-shotting average enemies far away and standing still if I aim manually. Has armor-piercing, good for sniping turrets and robots as well. svcky VATS percentage. I use VATS only in the rare occasion that I need to snipe two enemies simultaneously, since my current AP allows two shots in VATS.
Automatic combat shotgun -- don't remember the exact stats nor where I found this gun, but it has an unmodded 80 damage, fires repeatedly, and has high accuracy. Originally came with medium scope, but I didn't need another long-range weapon. So I modded it with reflex sight for short range. When firing repeatedly (12 rounds per clip), its high damage can take down tough and fast enemies at close range like Yao Guai and radscorpions without VATS. I do have to conserve ammo, and buy shotgun shells when I can. 10-20 rounds may not be a lot for automatic rifles and pistols, but it is for shotguns.
Righteous Authority -- the only legendary weapon I have. It served me a bit in the early going, but now it pales next to my modded 10mm pistol with 31 damage.
Automatic Institute Rifle -- 25 damage, and similar stats to my other automatic weapons. I love automatic weapons, so I carry this one just to use my cell ammo.