TL;DR With Field Choke, Shot Package, Rifled/Reinforced Barrel, you've obtained all you need and the final perk is your preference. Barrel: Field Choke (Many will argue to go with Accurized Ballistics, because it offers a miniscule impact increase. At this point, this increase is useless since you will be at a one-shot impact anyways. Thus, range will be more helpful and Field Choke provides the most in this perk family.) Perk 1: Shot Package (Many will argue Rangefinder is "ok." They are not the same. Shot Package makes the SPREAD more narrow, which actually increases the range intrinsically, so more pellets connect. Rangefinder just increases the effective range, but that's not very far for a shotgun and the pellets will continue to spread making this perk not that effective.) Perk 2: Rifled/Reinforced Barrel. (They both provide the same amount of increased range. Up to you whether you want stability or reload speed penalized. Neither really matter, since both your stability and reload speed will be atrocious no matter what you do.) Perk 3: Up to you (Really a toss up here. Most will argue for kneepads for increased slide distance, but I'm bladedancer and already use the class perk that provides increased slide and these don't stack. Final Round or Luck in the Chamber are irrelevant, since you're one shotting anyways and won't benefit from any damage increase. You might as well use Army of One, since 95% of your kills will be unassisted and melee/grenade cool downs are helpful.) TL;DR With Field Choke, Shot Package, Rifled/Reinforced Barrel, you've obtained all you need and the final perk is your preference.