I should also mention I have all the DLC's
I am playing hardcoe mode and thus I have to think about ammo weight, which can greatly affect my weapon choices.
I tried out a riot shotgun when I stormed Vault 34 and it's swarm of ghouls. I ran out of ammo for it half way through the vault. I was packing about 100 rounds for it, as the rounds are quite heavy. I then proceeded to repair and use a 10mm submachine gun I found in the vault and made it through.
I had also brought a Marksman Carbine and tried using that on the ghoul swarms, but it didn't work too well at close range with fast enemies that circle around you and such.
I so far have decided to stick with the Gobi for my long range rifle, but my weapons for mid range, close range, and pest control are still undecided. I acquired the All-American (a unique marksman carbine) and am thinking about using it as my mid range gun, and as pest control as 5.56 ammo is cheap, and repair costs don't matter thanks to my heap of repair kits. I am still open to suggestions for a mid range and or pest control gun.
My biggest Problem is close range. I found the Riot Shotgun to be quite ammo hungry and it's ammo weighs a lot. I am debating on forking over the caps for "Sleepytime" but am unsure if it will pack enough punch for some of the nastier scenarios at close range. I have not tried the other SMG's as I usually used guns that were not automatics. I had thought about the 12.7mm GRA SMG, but it's ammo weighs almost as much as 12 gauge rounds and it chews through it a lot faster.
I am not sure what I should do for close range. I have all the shotgun perks, so maybe I should stick with the riot shotgun, maybe vault 34 was just a bad first test for it. Maybe I should go for an SMG or other automatic weapon. Maybe I should use a pistol that packs a big punch.
Note that I will not be using a mini-gun or LMG for close range. They are heavy and eat too much ammo for my character, and also just don't suit him well.