The next weapon up on the list of “Final Fantasy VII” ultimate weapons is Barret's powerful Missing Score. This one is quite tricky to obtain and can be easily missed. It is found at the end of disk 2, when Cloud and the party are heading up to fight Professor Hojo. If Barret is in the party, the Missing Score will be in a chest along one of the many stairs to the top of the tower.
However, if Barret is not in the party, the Missing Score will not even spawn, and it will be completely impossible to go back and get it. Like most all of Battet's other weapons, Missing Score is long ranged, meaning it can do the same damage from the back row as it could from the front, and it can hit otherwise unreachable enemies, such as flying ones.
One trade off for Barret's Missing Score and the fact that it is long ranged, is the fact that, while most other weapons for characters give addition stats to the character, Barret's weapon substitutes the extra stats for the long range status.
The Missing Score functions in battle via AP from Materia. Depending on the amount of AP corresponding to the Materia equipped in each of the eight, zero growth slots on the Missing Core, the weapon will power up. The more AP equipped to it, the stronger the damage will be.
For this reason, Barret's Missing Score is a prime catalyst to preform the Overflow damage glitch with. If equipped with eight mastered Knights of the Round Materia, due to the sheer amount of AP held in those Summon Materia, Barret is able to deal enough damage to cause Overflow.