This is some strategic loadout ideas for the Juggernaut. It is based largely on opinion, and these suggestions may or may not fit your play style or level. Please do not change the existing loadouts, except to fix grammar or spelling. Instead add a new loadout to the article.
The weapons that are pre-bought when you start playing the game.
Primary: R870 - Probably the worst of the three pump-action shotguns. It is literally inferior in every single way to the SPAS 12. As a result, you should trash this thing quickly.
Secondary: Beretta Px4 - A ho-hum pistol that performs averagely. Nothing bad, nothing amazing.
The default loadout is a fairly typical fare - Two okay weapons to start off with. Nothing exciting, nothing interesting. Not much of a strategy for this. You'll want to replace your weapons ASAP with something more effective. Always try to pick and take out weaker enemies like Engineers and Generals. Snipers can be fairly dangerous at range, but up close, you can kill them very easily. Watch out for Mercenaries or other Juggernauts.
The goal with this loadout is to weaken your opponents by spraying them with acid, them running away before they kill you. After a while, they die or lose most of their heath from the acid.
Primary: Cobra -This shoots acid, and if you hit someone at all,they can lose a lot of their health. But it won't kill fast.
Secondary: Katana, or a long range handgun. -the Katana could save your life as you run away, it's also very powerful at close range. Or, you could use a pistol with good range to finish off your enemies once they are weak.
Attachment: Resistance - So you don't poison yourself when you get too close to enemies.
Skill: Resistance: -Protects you from all elemental effects, including your own.
Killstreak: Anything works, but my suggestion is Combustion. Sets nearby enemies on fire.
Primary: Judgement - Highest damage possible.
Attachment: Loudener - Increases OHKO chance of Judgement.
Skill: Immovable Object - "You can never have too much armor"
Armor: Titanium Plate - The Juggernaut has lots of health anyway so put on more armor.
Strategy: Weaken the enemy armor(you don't have to empty the entire clip) with the Secondary weapon as you close in and then finish off with the Judgement.
Primary: Judgement - Highest range and damage out of all the shotguns. Plus they forgot to add a lever action sniper
Secondary: Eh, go ham with what you want.
Attachment: Long Barrel - Increase range of the already best in class range
Skill: Immovable Object - So you can be beefy and thicc
Armor: Kevlar Vest - Increased survival rate
Killstreak: Go ham
Strategy: TL; DR, If the sniper ate way too much at Thanksgiving and became dummy thicc. Because the Judgement has the best range and damage, it makes it quite the sniper(well, for a shotgun). Along with the fact that if you aim near the head, it's damage multiplies rapidly. Long Barrel increases your good in-class range, but overall poor range. Your goal is to live up to your name, the Juggernaut, and eliminate your enemies like paper over a fire. This class rewards longer range engagements which is why I chose the Judgement. Armor wise, you can choose the Titanium plate but I prefer the Kevlar due to it's second best armor stat and no downside.
Primary: Flamethrower - Not the best elemental but it works well
Secondary: Go ham
Attachment: Fuel Injector or Deflection Plate - Fuel Injector will help with the relatively low damage of the Flamethrower and the Deflection Plate will help you survive CQBs. Which one is better is up to you and your play style.
Armor: Blast Plate - You're using a fire based weapon. The Blast Plate will reduce self damage from the Flamethrower.
Skill: Immovable Object or Resistance - Immovable Object helps with the low armor amount of the Blast Plate. Resistance will prevent status effects like Electricity or Poison. Choose what works well with your play style.
Killstreak: Combustion - Again, not the best of Killstreaks on the Juggernaut but it works well due to the short range of the Flamethrower.
Strategy: You're already using the worst Elemental and Killstreak on the Juggernaut so what gives? Well this class actually works better than you'd think. The Flamethrower has a decent DPS and won't hinder your HP/Armor HP for too long. The Blast Plate will reduce some of the self-damage you inflict upon yourself and your Killstreak will reduce a little more damage you inflict upon yourself. Basically, the goal is to not kill yourself while killing enemies. There are better classes for this, but there's so much that fits the "Fire" category and makes a nice challenge class.
Primary: KSG - One of the best shotguns in the game; it has power, a huge number of shots per clip, and a great rate of fire. One of the best of the best.
Secondary: Go with a pistol with good range and accuracy, to make up for the low range of your primary.
Attachment: You've got a choice; three attachments are all really good for the KSG. You could go with a Hair Trigger to give it an even better ROF, a Loudener to give it even more damage, or a Long Barrel to give it even more range. All of these have their place.
Armor: Either Kevlar or Titanium. Alternatively, Oobleck, but you'll need Immovable Object to really make good use of it.
Skill: Either Immovable Object or Resistance. The others aren't that good.
Strategy: Walk up to a dude. Unload. Murderize him. Repeat. It completely shreds light classes in under a second, and for heavy classes... Well, it depends. If you're fighting a Merc with a rocket launcher, you might want to use your secondary, or go activate your killstreak (if it's available). If it's a Merc with a Machine Gun, then you can just walk up to him and decimate him, he will not kill you before you obliterate him. Against Juggernauts, if he has a shotgun or a grenade launcher, again, take heed. But if he's got an Elemental, then he may as well just save you some time and just fall to pieces right there. Otherwise, your biggest worry is definitely Snipers. If you can get close to them, you'll murder them as quickly as you murder Engineers and Generals. If not... They'll probably two-shot you.