to bring up the upgrade menu ingame, you must buy the 1st upgrade under the "Core" category in the bottom right which costs 4 components.How to
When aiming down sight with
at a heavy weapon, hold
and jack will retrieve the weapon.You do not need to
-kill with the weapon
-Fire the weapon
-Be in an active fight
-Pick up the weaponLocations
I recommend Act 2 Chapter 4 as you can get 4/5 weapons in it.
then move onto Act 2 Chapter 5 for the Cryo CannonRL-4 Salvo Act 1 Chapter 3
When fighting in the street to assist Lizzie a Scion will appear midway through the battle at the other end of the street, you will know when he appears because Cole will say "Here comes their MVP!"
In the same fight you also get the option to call in support from Baird the choice between Salvo Guardians or Trishot Guardians.Act 1 Chapter 4
At the end of the chapter fighting the Swarmak after Cole rides a motorbike into its mouth you are in a new location outside look behind you to see a salvo on the floor.Act 2 Chapter 4
A downed Condor site North-West of the East Comm tower has Salvos.TrishotAct 1 Chapter 3
when fighting in the street to assist Lizzie you get the option to call in support from Baird the choice between Salvo Guardians or Trishot Guardians.Act 1 Chapter 4
While in the hotel you will move into a ballroom celebrating parents of settlement 2 (it has a purple stage in it) filled with "Rejects" a Trishot can be found leant up against a table near the stage.
Another one can be found attached to the Stump on stage slightly later on in the same chapter.Act 2 Chapter 4
A downed Condor site North-West of the East Comm tower has Triguns.MulcherAct 1 chapter 4
After defeating the first flock and moving out into the street a Scion with a Mulcher will be stood on a car half way down the street.Act 2 Chapter 4
head to the mine you'll arrive at a large lake when you forced to defend the lake as you wait for jack to cut open an elevators door near the end of the fight 2 scions with mulchers and bastions protecting them will start attackingAct 3 Chapter 2
The Mulcher can also be found in the initial fight in "The Rocket Hangar" (Credit to TheLightMaster)Cryo CannonAct 2 Chapter 5
After a lot of story and stopping the freezing you will slide down an ice tunnel, Del will say "hey want to tell me what the hell Niles is talking about?" there will be a Cryo cannon on the right before you enter a fight you must pick it up drop it then you can have jack retrieve it.BuzzKillAct 1 Chpater 3
There is also a Buzzkill in the section when you assist Lizzie. It's on the back of a vehicle towards the end of the map, near where the Scion appears. (Credit to KAW 24)Act 2 Chapter 4
when entering the mine to retrieve explosives, you make a minor drop in to enter the area in which Marcus will say "probably an old Nethercutt mine" follow the left side wall in to a small broken shack with a bunch of logs round it on the floor will be a Buzzkill.
Another one can be found shortly after when defending the ice lake while waiting for jack to rip open the door, just left of the door where a scion was standing.Act 3 Chapter 2
The Buzzkill can also be found in the fight while escorting the rocket with the satellites during "The Rocket Hangar" (Credit to TheLightMaster)Act 4 Chapter 2
It's lying on the ground in front of you, after deciding who you wanna save and exiting the building, right where the exploding Juvies and other enemies attack you. (Credit to CoreScan)Notes
-You can have a human player playing as Jack and get the achievement (confirmed by Kaizoku Umi)
-progress is added (20%) the moment jack drops the weapon at your feet.