So im thinking about doing a pure shotgun build. However, ive tried a few times in the past, playing on hard and very hard difficulty, and it didnt work out to well. It just seems the total damage cant really compete with other high powered rifles and melee weapons. The shorter range doesnt even bother me that much, though it seems to become an issue when facing creatures like deathclaws.

So, can you guys recommend some perks, weapons, ammo, etc that would be good to use, preferably on hard or very hard difficulty?

Shotgun Surgeon is a must.

Slugs vs every thing tbh, except cazzadore'.

The best early build I've ever played was with this set up..

Dexterity 8.
Perception 6.

Small frame.
Repair, guns.
Rapid reload, 2nd perk, shotgun surgeon.

Equiped a caravan shotgun, by the time I had reached NoVac.. every creature from north of Goodsprings to south of the Mojave outpost was dead.
Every giant rad killed in seconds on normal, every nightstalker, every gecko.

By Novac I had a found hunting shotgun and the rest of the map was even easier.

Slugs make you a lot less accurate and I wouldn't recommend using them. They should be reducing the spread of the weapon but they reduce player spread which is a big difference. With lower spread shotguns you might not notice it as much but try a sawed off one and you will see what I mean. Instead of 14 projectiles having a huge spread you end up with 2 projectiles having a huge spread which makes it very difficult to hit anything. Also you don't get your hulls back which means you can't craft any new ammo and will be relying on loot and stores to stock your supply which for me was a real pain.

Also another thing I noticed about the sawed off/Big Boomer is that you can't get a critical hit at all. People think you need to get a sneak attack but it doesn't matter because you will never get critical damage. You will still get double damage from the sneak attack but won't get the weapon's critical damage added.

Now of course if any patch has come out since the big one that may have fixed the above you can forget about that. I haven't played in a month or more.

Overall I found shotgun builds too hard to use (at least on very hard) until you get to the hunting and riot shotguns which made the game way too easy.

Shotgun Surgeon is a must but I am guessing you already figured that out.

Shotgun really relies on high action points to be effective against tough enemies. They have a pretty good punch most of the time, but they shoot slowly, and against things like deathclaws, you really need to be hitting them in the head to have the desired effect. (The riot shotgun is the exception: it shoots fast, but it has all the accuracy and precision of a hand grenade). On the flip side: the shotgun is a cheap hard hitting weapon that will completely obliterate most enemies in the game. And unlike what the other person said, there's really no point to abandoning buckshot. It's cheap and common, and with Shotgun Surgoen you take 10DT off any enemy, which negates the armor of most. Deathclaws, Giant Radscorps, people in power armor, those are pretty much the only ones you'll really want to switch to slugs for. Slugs are more expensive, save them for when you really need them.

For a dedicated shotgunner I'd advocate high agility for the AP, Fast Shot trait for bonus rate of fire (shotguns are already inaccurate and short ranged, you don't lose anything here), with above-average strength if you're playing on hardcoe since shotgun ammo is heavy. Shotgun Surgeon is the obvious mandatory perk, and Action Boy/Girl. Again: since shotguns shoot slow and reload slow, you need to make every shot count. Learn to love VATS when you're dealing with tough enemies or hordes. Math Wrath may be worth considering for this purpose if you were going to get Science skill for the hacking.

Oh, and just some general wisdom. Like real modern day shotgunners in the military, reload constantly. Unless you have an enemy actually in your face gnawing on your intestines, shoot once and then reload. Your magazine is tiny, don't let it get empty, because when you need to fire multiple shots you need to do so urgently.

In the end, I think it depends on the player. Ive had alot more luck on normal with the single shot and the hunting shot gun using the slugs than I did with the sawed off or the riot shotgun. The slug up close in the 20 ga single shot killed just about anything. the 20 ga slug in the lever action shot gun was even better. The hunting shotgun with slug is the best the others just got worse for me. As of now I am not even using a shotgun, im using a unique .357 magnum revolver shooting .38 special ammunition and I am getting kills left and right. Not good against armored targets but the shotgun slug isnt either.

If you are going to be reloading check every roving caravan you come across. Typically every oneof them I noticed has free shells or hulls that you can get for nothing. Then you would either have to break down ammo you have and dont use or head over to the gun runners and buy all the powder and primers you can. That is what I do. I sell armor and guns I dont want to the gun runners get a nice hefty price and then I wipe them out on primers and powder and reload my own.

Shotgun Surgeon + Dinner Bell is hawt.

A spread of 1 makes it pretty damn accurate.

Dexterity?

Anyways, all you need for a good shotgun character is a good shotgun.

And Action Points is useless; if something get close switch to Riot.

you should consider getting the cowboy perk, available from lvl 8. in terms of damage, it puts the leveraction shotgun on par with the hunting shotgun.
but with the leveraction having the higher ROF, and the advantage of firing 20ga instead of 12ga, which are more expensive, and way rarer, especially in the early game stages.
leveraction+cowboy+shotgun surgeon+slugs=pure carnage

-80+ Guns
-Trigger Discipline
-Shotgun Surgeon
-Better Criticals
-Finesse
-Cowboy-Works for the lever-shottie.
-Slugs and Magnums.
-Dinner Bell or Hunting Shotgun with mod magazine and choke tube.
-Riot Shotgun.

Trigger Discipline make shotgun better at the range which isn't great and worsen close quarter perrformance.
Better Criticals and Finesse is unnecessary as Shotgun critical is weak.

Dinner Bell has a spread of 1, making it great for mid-range.

VATS Shotgun Character:
Shotgun Surgeon, And Stay Back, Hunting Shotgun+, 9 or 10 Perception, 9 or 10 Strength, 9 or 10 Agility, Center of Mass, Sniper, Action Boy, Math Wrath, Commando, etc. perks.

Give Cass a Hunting Shotgun......critters will die like flies as she blasts them to pieces with it.

Give me a Hunting Shotgun+ with the perks I listed.......Deathclaws will die like flies as I blast them to pieces with it. I love the Hunting Shotgun+ along with my devastating perks.

While I love my fully modded Hunting Shotgun...the lure of the BAR is awfully tempting.

I would agree with that. Shotguns rock, especially the lever action with Cowboy. But shotgun crits are not impressive.

And we all wish there was a BAR in this game. Mods are nice, but having one in this game would be awesome. Stick a BAR in a DLC, and I will download that an instant!

http://www.newvegasnexus.com/downloads/images/37002-5-1293312716.jpg

There is...it's called the "Automatic Rifle", and it is in the Dead Money DLC. If you're on XBox you can get it now, otherwise you'll have to wait two weeks for it to come out for PS3 and PC.

The shotgun, with all relevant Perks and loaded with Magnum Rounds is a most effective weapon up to 7 to 10 yards. I recommend the Riot Shotgun