Equipment
Next let's talk about the second thing our MC can add points to, Equipment.
Now the equipment rarity in the og system goes from 1 through 6. It is not known if 6 is the limit.
Here the rarity corresponds to the amount of skills an equipment has.
For example: Sword with rarity 1 has 1 skill and a sword with rarity 6 has 6 skills.
The skills as hinted at in the original story adds up as they increase in rarity.
For eg. Sword with rarity 5 has 5 skills, then sword with rarity 6 will have those same 5 skills and then an extra different skill will be added.
Now adding BP in this Equipments doesn't increase its rarity by one to one. It doubles each time.
So Here is a nice run down for every rarity.
First is The level of rarity. (This is the required BP). [This is the total amount of BP used to reach that level]
Level 1 = (1) [1]
Level 2 = (2) [3]
Level 3 = (4) [7]
Level 4 = (8) [15]
Level 5 = (16) [31]
Level 6 = (32) [63]
Now there are various kinds of Equipments the MC can add BP into.
Accessory, Weapons, Shield, Helm, Torso, Arm, Feet
In the case of Accessory it is Rings of Different rarities, for weapons it is two handed swords of different rarity.
But mostly the MC will add BP into Weapon, which will result into a 2 handed sword of different rarities.
CREATORS' THOUGHTS 
Avi2112
Avi2112 This double BP increase is present in almost everything in the system.
Weekly Power Status
-- Power
Ranking 
-- Power
stone