There are many weapons in Death Stranding 2 that are armed with MP bullets, and players will encounter one, the Assault Rifle [MP] Lv1, near the beginning of their time with the game. While the description of this weapon does provide some information about MP bullets, players may still be confused about exactly how this type of ammo works. This guide is here to alleviate that confusion, and it will give players a solid understanding of MP bullets in Death Stranding 2.
It is believed that “MP” stands for “multipurpose,” though that does not appear to be explicitly stated in-game.

Related
Death Stranding 2: How to Repair Cargo
Cargo is as precious as connecting humanity to the Chiral Network in Death Stranding 2, so how can players repair it against damage and Timefall rain?
What Are MP Bullets in Death Stranding 2?
MP bullets are a type of ammo that is effective against any target, be it a human, a mech, or a BT. This makes weapons with the “MP” designation extremely versatile, as they can be used in any combat encounter. That said, it is important for players to be aware of the fact that MP bullets do not have all their functionality at the beginning of Death Stranding 2.
Indeed, while MP weapons can be used against both humans and mechs straightaway, they are not effective against BTs until after Order No. 005, which centers around delivering Prototype MP Bullets to the Former Geophysics Research Lab, is completed. This means that players will need to deal with some BTs before their MP weapons receive the anti-BT effect, as that type of entity appears during Order No. 005, and they will need to rely on Blood Grenades during those encounters.
The Prototype MP Bullets that players transport during Order No. 005 cannot be used to give a weapon an anti-BT effect during the mission. While the delivery of those bullets ultimately unlocks that effect for all MP weapons, the item itself is simply a piece of cargo in Death Stranding 2, not ammo to be used.
Are MP Bullets Lethal in Death Stranding 2?
Weapons armed with MP bullets are nonlethal when used against human enemies. MP weapons are thus great options for Death Stranding 2 players who want to take on MULEs without killing them, and that approach is generally recommended.
With respect to BTs, MP bullets do kill them, and this will be confirmed for players almost immediately after completing Order No. 005 and unlocking the anti-BT effect. That said, Blood Grenades can still prove very useful against Death Stranding‘s BTs, and players are advised to keep some in their grenade pouches if they expect to encounter those entities.