To build this monster, you will need

Chassis: Rocket
Compact stock
Semi-auto
quad cluster
slug
heavy barrel
sticky
manual
Remote control scope
Super slow

The launcher, without any upgraded parts (level 2 or 3) will do about 81 damage if it sticks to an opponent and it is detonated, so it's guaranteed damage is insane. If one detonates the rocket directly before it can touch their opponent, the quad cluster comes out and instakills, and it kills all within a melee range of the detonation point, so if there are people on a point, they're all gone. A LOT FASTER than pyro builds could dream. It must be noted, though, that one must learn their timing for the quad cluster release for it to be effective. This can easily be honed in the testing range on the game.

SInce the rocket itself is faster than you, if your team is about to lose an objective (let's say, a capture point, or there's a hammer guy running away), you can catch up with your rocket instead of you, and instakill the player(s) that were about to wreck your team's good time.
Because it is sticky and manual at the same time, it gains more versatility in two ways. 1. If stuck to a surface at a high height, it will stay until shot at or detonated, so you can spy on everyone. 2. You can stick it to a cap point and leave it there, so that you can see with your rocket cam if someone is coming. When they come, detonate the rocket, and the quad cluster will severely damage all enemies on the point.

The final piece of versatility this monster has is for the beginning of matches. On many maps, all players are crowded into one tight area. When the countdown finishes, rapidly double click to have the cluster come out and wreck everyone.

Some people may ask if it is good with other payloads. The answer is yes, but each one comes with a tradeoff. If you go tesla, it will still have the mentioned instakill effect, and it will work better on sheilded opponents, BUT each bomb of the cluster will do around 25 damage instead of 34, and therefore if you detonate and the opponent moves a little, if 3 out of 4 bombs hit, NO INSTAKILL. Can this weapon work with Pyro. Yes, If you do that, it will fully kill with and without quad cluster, BUT it will not be immediate like slug. Now the juice and health can work, with juice in jackhammer and health in blitz, but you don't need to heal your team mates if no one is hurting them any more, do you? :D.

This is one of the best weapons in Loadout, period. Though it works in all types of matches, it is best in jackhammer and blitz (use with spawn point!?). I hope everyone enjoys this weapon, and I hope havoc ensues!