Barret Wallace Ultimate Weapon

Barret’s Ultimate weapon, Missing Score can be found in a chest on the stairway leading towards Hojo during the Midgar Raid on Disc 2 (Sister Ray). This chest will only appear if you have Barret in your party, so be sure to have Barret in your party otherwise you cannot obtain this weapon (legitimately). To attain max damage with this weapon, you must equip the weapon with materia with the largest amount of AP (a few mastered Knights of the Round; the way this is calculated is as follows:

{ [Total Attack power x (Total AP from Materia on Weapon · 1000)] · 16 } + 1. In lameman terms, Stick all your materia that is mastered, which took ages to level up. i.e. knights of the round…

There is a glitch that exists in this game called overflow and only works with Barret’s and Vincent’s weapon. Basically, what you have to do is equip 4 or 5 Mastered Knights of the round, Deathblow, and give Barret a few Hero Drink’s and you will be able to one-shot any boss (apart from Ruby weapon). I will post some vids in the Media section in action. It does take ridiculously long to master knights of the round, but the satisfaction you will get from one-shotting Emerald weapon will pay off.