.390 | Halo Alpha+BreezeWiki

.390-caliber ammunition is an ammo size used by the UNSC MA2B Assault Rifles. It is a significantly larger round than the M118 7.62x51mm round used in the MA5B (7.62x51mm = 0.308 caliber). The .390 comes in at least two varieties: the standard armor piercing rounds and shredder rounds made from depleted uranium.

Trivia

This round size may have been specifically created for the MA2B Assault rifles - its modern counterpart is an obscure Soviet Assault rifle round.
Most human weapons in the Halo series use current ammunition sizes based in real life, this round is among the several that don't.
Spartan-II Blue Team used this round size in their MA2Bs when they apprehended Colonel Robert Watts.

Appearances

Halo: The Fall of Reach (First appearance)
Halo: First Strike
Halo: Ghosts of Onyx

v d e List of UNSC Infantry Weapons

Melee Weapons	CQC WS Combat Knife • Humbler stun device

Pistols and Submachine Guns	M40 Pistol • M6 Series (M6A • M6B • M6C (SOCOM) • M6D • M6E • M6F • M6G • M6H (M6H2 • Whispered Truth) • M6I • M6K • M6J) • Pocket Pistol • M7/Caseless SMG (M7S) • M20/PDW • Machine Pistol

Assault Rifles and Battle Rifles	MA2B • MA3A • MA5 Series (MA37 (MA5) • MA5B • MA5C • MA5D • MA5K) • BR55 series (XBR55 • BR55 • BR55 HBSR) • BR85 Series (BR85 HBSR • BR85N) • M392 DMR • M395 DMR (M395B)

Shotguns	M90 CAWS Shotgun • DTM/Law Enforcement • M45 Tactical Shotgun (M45D (Lawgiver • Blaze of Glory • Oathsworn) • M45E) • Underslung shotgun

Sniper Rifles	SRS99 series (SRS99 AM • SRS99C-S2 AM • SRS99D-S2 AM • SRS99-S5 AM (End of the Line • Arrow of Time • Nornfang) ) • M99 SAR

Anti-Vehicle Weapons	ARC-920 (Whiplash • Arclight) • M19-B SAM Missile Launcher • M41 SSR MAV/AW Rocket Launcher (SPNKr EM • SPNKr EX • SPNKr Prime) • LAU-65D/SGM-151 Missile Pod • W/AV M6 G/GNR Spartan Laser ("E"-variant (Endgame • Selene's Lance)) • M149 Magellan RCL • LAU-1810/SGM-151 • M555 Electromagnetic Launcher • M57 Pilum Assault Weapon (Ad Victoriam • High Five) • M80B MLRS

Machine Guns	.308 Cal. LMG • AIE-486H HMG • HMG-38 • M202 XP MG • M247 GPMG • (M247H HMG (Etilka)) • M343A2 Minigun • M739 LMG (Appetite for Destruction • The Answer) • T261 Lucifer Arm-Mounted Gatling Gun

Flamethrowers	M7057/Defoliant Projector • NA4 Flamethrower

Grenade Launchers	M301 40mm Grenade Launcher • M319 Individual Grenade Launcher‎ (Pro Pipe) • M363 Remote Projectile Detonator • XM510 Multishot Grenade Launcher • MLRS-1 Hydra Launcher (Typhon • Echidna)

Explosives	102mm HEAT • C-7 Foaming Explosive • C-12 shaped charge • Fougasse • M168 Demolition Charge • M9 HEDP Fragmentation grenade • M383C LSC Demolition Kit • Napalm grenade • Satchel charge • Smoke grenade • Sonic grenade • Thermite-Carbon Cord • Thermite grenade • Flashbang grenade • Type 18 Magnetic/Bayonet-style Claymore

Cartridges	M225 SAP-HE • 12.7x99mm • 14.5x114mm • 0.390 caliber • 0.450 caliber • M118 7.62x51mm FMJ • M634 X-HP-SAP • MUTA-AP-09334 • M443 Caseless FMJ • Soellkraft 8 Gauge Shell