Vorph
Basically youre looking for anything with outlaw and rampage for pve shit. If you get an outlaw rampage roll on any gun, chances are it will be usable/servicable even if they are not the "meta" right now. Even a straight up rampage with some other shit perk will be better than no rampage. Some will say other shit but I find these rolls to be the best for PVE. For consoles look for shit that has a good aim assist on it. you can see the hidden stats on DIM (destiny Item Manager)
PC and console is different though. I have not played console in a long while and yeah I used a shit ton of ARs on console when I did play (yr 1 when the 450 ARs were the meta). The pulses I do like when they come full auto too. For some reason they seem to fire better and quicker than I could ever pull the trigger in the timing, so look out for those.
Ive been mainly using Austringer that I rolled with outlaw and rampage on it. In my energy slot I change it out quite often but I find for gambit I love the Jotun since most of the blockers have solar shields, it takes 3 shots to down a captain and you can do it at range too so you wont be smacked. Its almost like a heavy in this regard, it hits hard, sort of tracks, and plenty of green ammo around. I used to use full auto shotties like Ikelos before, but since they nerfed the fire rate I find them less effective and I dont even use it anymore. Other shit I use is snipers, I definitely find myself using riskrunner a lot too. For heavy since they nerfed the HMG dmg, I find myself using the grenade launchers. I found a nice one form last Iron Banner which has spike grenades (more dmg on actual hits, not splash) and quickdraw and snapshot sights. But for gambit if youre still gonna invade HMG is still best because you can take out a full team with one brick if your aim is good. I also like the new slower firing HMG like the one form menagerie too, tons of range and they hit hard.
Bows are nice too to break shields but I find myself not using too many bows. But if youre gonna be doing some of the harder nighfall or other dungeons, they come in handy against shielded enemies.
For PvP I like they bygones the drifter sold in season 4? Full auto and kill clip. I also use Ace of Spades and the thorn which I just got last week a lot and I have a full auto and outlaw Swift Ride XE8375 which dropped from one of the forges which is nice too. Jotun works well, its kind of a meme gun though in crucible, Erentil FR4 is nice too, fucking thing maps people when you get used to the charge time on it. Ive also had good success with Galliard-42 XN7568 600 rpm kill clip auto rifle if the match is not too sweaty. But it jsut does not compare to the TTKs of hand cannons and pretty much your tracking has to be on point hitting mostly heads. Suros is also good with the spin up perk too, double if youre using the titan exotic chest which partially reloads your mag on auto rifles. Auto rifles are in a tough spot. They like to be used in medium range, get out ranged by pulses and out TTKed by them too. And hand cannons in their respective range is 3 headshots so, ARs just dont compare. Those hard hitting 4 burst pulses like go Figure or Blast Furnace, youre talking about only 2 bursts to kill someone with a nasty .73 TTK if they hit headshots.
PVe shit though other than high end pve, it just does not matter what you use really. most of the PvE day to day like strikes, missions, forges, menagerie just does not matter, use whatever feels best to you. Its only the high end stuff like raids, nightfalls etc, that you have to coordinate on shield breaks and shit like that. This is where a good arsenal of snipers is good to have in all flavors, etc...
Not sure if its still available but grind out the breakneck (gambit pinnacle) if you like ARs for PvE shit the thing melts. Also not sure if its avalable but zavala had the Loaded Question which is great for PvE with reservoir burst perk. Grind out as many of the pinnacle weapons as you can, they are all good.