There are two guns that shoot rocket dogs.
Infinite ammo, full auto, has a sniper scope, barks when fires, small Liberty Prime explosions when it collides.
Can be found in Chet's general store in Goodsprings, takes no ammo. AwesomeDogSniperShotgun is a full auto sniper rifle that fires 10 dogs per shot. Works more or less like regular bullets. Awesome Dog Cannon is a FatDog Launcher. Smaller AOE than a FatMan.
Mod requires nothing more than the base game.
Two guns now.
awesome dog cannon - xx000DC0
awesome dog sniper shotgun - xx00109E
If you're updating, unequip the old gun first, save, update the mod, load, you'll have to buy the guns again from Chet or use the console.