Basis of the build:
- The Flakker damage overwrite: the base damage for the Flakker’s pellets takes the on-card damage of the current active weapon.
- Jack’s Sponsored By with Scav manufacturer: swapping from a Scav weapon instantly reloads the next weapon, bypassing the Flakker’s slow reload speed.
- Jack’s High-Frequency Trading (9/5) allows for crazy fast weapon swapping.
- Jack’s Leadership and weak-ish Digi-Jacks allow for more kill skill activations, further increases flakking damage.
Goal: maximizing DPS of the swap in continuous, un-pause-able combat.
Pros & Cons: available early, insanely high damage output, but requires relatively precise positioning for shots, tricky/ineffective against small or melee range targets.
Skills & Gear:
Level 25: http://www.thepresequel.com/Jack/00000000000000000000000000550015005001
Level 50: http://www.thepresequel.com/Jack/50105100000001410500110000550015005001
Level 70 DPS http://www.thepresequel.com/Jack/50105100040505550000115101550015005001
Level 70 Survival http://www.thepresequel.com/Jack/50105100000005550504115101550015005001
Weapons:
Casual Flakker 
(x5, any level)
fwap a Nukem (or a good Torgue Launcher)
Zim (or any common Scav pistol)
Fridgia 
(or a good Cryo gun)
Class Mods:
Eridian Vanquisher (+High-Frequency Trading)
Unbelievable Hero (+Believe +Integrity +Gun Damage)
Early game: Economist (+Weapon Swap Speed, +Gun Damage)
Shields:
Haymaker
Shield of Ages
Deadly Bloom (if spec’ed into You Have My Shield)
Grenade Mods:
Longbow Cryo Singularity
Longbow Cryo
Oz Kits:
Tranquility
Systems Purge (when using Fridgia in atmosphere)
Combat routine:
Step 1) Swap to Scav weapon -> swap to Flakker (increases mag size & instantly reload)
Step 2) Fire the Flakker -> swap to RL -> all flaks went off
Step 3) Swap to Flakker -> repeat step 2
Step 4) If the Flakkers empty or almost empty -> repeat step 1
Tips:
Keep the grenade count low to activate Just Compensation, increasing mag sizes.
Move around to respawn/kill your Digi-Jacks, triggering kill skills.
Noteable fights:
RK5: stay on ground level forcing RK5 to lower itself into flakking range.
EOS: jump toward it as it spawns to maximize pellets hit, can OSOK w/ prep.
Difficulty:
Gear acquisition: Low
Combat execution: Medium
Early availability: Lvl 8-9 (Flakker drop, 5/5 High-Frequency Trading)