Ammunition (AAO)

==Pistol Ammunition==
===11.43x23mm (.45 Caliber)===
The 11.43x23mm (.45 Caliber) round is primarily used by the Model 2511 Pistol and the M10 Submachine Gun. A lighter alternative to the more standard 12.7x40mm round, the .45 Calibre offered a more manageable weapon with better rate of fire, though traded this off for lower stopping power.
====Automatic Colt Pistol Hollow-Point Explosive====
The 11.43x23mm Automatic Colt Pistol HPE (also abbreviated as .45 ACP HPE) ammunition type had the power and explosive potential to penetrate body armor, and explode about halfway through the body, maximizing damage. As a result, this ammunition type round could kill most unarmored sentient and insentient beings with a single well-placed shot.
====Armor-Piercing-Explosive-Incendiary====
The 11.43x23 Armor-Piercing-Explosive-Incendiary (abbreviated APEI) ammunition type had the power and explosive potential to penetrate body armor, explode about halfway through the body, and ignite, maximizing damage. This ammunition type round could kill most unarmored sentient and insentient beings with a single well-placed shot.
===12.7x40mm (.50 Caliber)===
====Semi-Armor-Piercing High-Explosive====
The 12.7x40mm round saw widespread use in the popular M6 Series and its successor, the SM6 Series. Although possessing somewhat excessive recoil, its stopping power and effectiveness in combat against technologically superior foes made it viable for continued use for sidearms. It was also used in the SRSS Nyegen 48.
====Armor-Piercing High-Explosive====
The AP HE round for the SM6 series is made out of experimental polymer composites designed to null the effects of body armor by keeping the force of impact to a small area, which increases the chances of penetration. Upon passing through the armor the round explodes, dealing severe damage to a target.
====Magnum====
The 12.7mm Magnum round contains an increased amount of propellant for an increase in muzzle velocity and stopping power.
====Armor-Piercing====
The 12.7x40mm Armor-Piercing round is a full metal jacket tungsten carbide slug with a lead core. The AP round also comes in a magnum variant.
==Small Calibre Rifle Ammunition==
===5x23mm (.20 Caliber)===
The 5x23mm caseless is the standard ammunition used in the M7, M12, and M14 Submachine Guns. The round's small size, high velocity and exotic made it ideal for use in close range personal defence weapons. Seeing fairly limited use during the Human-Covenant War in the M7 series of submachine guns, the 5x23mm round was dramatically improved in many of its ballistic qualities over its predecessors, seeing better muzzle velocity (which increased range, accuracy and stopping power) and vastly improved shield and armour-piercing qualities. Rather than the traditional setup of a bullet with an attached metal casing containing the chemical propellant, the 5x23mm round replaced the casing in favour of a solid 'block' of combustible propellant, in which the bullet was embedded. As the round was fired the entire block combusted, leaving nothing behind in the chamber, simplifying the firing mechanism and removing the need for a casing ejection port. The bullet's diameter was small, meaning its kinetic energy was reduced, however the comparatively large amount of propellant more than made up for this. In addition, the solid propellant block was similar in composition to the propellant of the M634 Experimental HP-SAP round, giving it greatly increased muzzle velocity. This allowed it to maintain a higher kinetic energy for longer, increasing range and lethality upon impact with the target.
====M412 Shield/Armour-Piercing-High Explosive====
The type of 5x23mm round most commonly used was the M412 S/AP-HE, or Shield/Armour Piercing-High Explosive. The bullet itself was coated in a polymer which acquired an electric charge while in flight, aiding the bullet's kinetic energy in depleting shielding and, although it had little effect on armour, giving an increase of about a third to the amount the bullet would drain a shield (at a distance of 500m). The further the bullet travelled in the air, the greater the charge it acquired, so this effect was at its most potent at longer ranges and nearly negligible at extreme close range.
The tip of the round consisted of a deforming ballistic cap; a lightweight element which crumpled upon impact with a target and gave the bullet superior aerodynamic characteristics. The bullet's armour-piercing core was a tungsten carbide penetrator with a self-sharpening tip; when it fractured upon impact, it would do so in a way that the remaining element was still a sharp point. The bullet's outer 'shell' was composed of hardened steel, which was webbed with prefragmented lines or weaknesses in the metal; the rear of the core penetrator was similarly fractured, and contained inside it a delayed timer fuze. A short amount of time after hitting a target and penetrating to its innards, the fuze would activate, blowing the penetrator apart along its stress lines, fracturing the external steel jacket and devastating the target's innards with white-hot metal fragments.
===7.62x51mm NATO (.30 Caliber)===
The 7.62x51mm round is in use in the MA5, MA6 and MA7 Series of assault rifles, as well as light machine guns such as the M21 Light Machine Gun. Although the round was relatively weak compared to alternative calibres, its accuracy and potential rate of fire, combined with negligible recoil, made it well suited for use in assault rifles. Following the Human-Covenant War more exotic and powerful ammunition types were available, increasing the effectiveness of the 7.62mm round so that it posed a serious threat to shielded and armoured Covenant infantry.
====Incendiary====
Not long after the installation of the MA7 series in to active duty came the introduction of incendiary ammunition. While not being able to punch as far in to tissue it has been found to be a highly effective weapon against unshielded targets, especially Unggoy and Flood.
====EMP====
The EMP round, introduced in 2574, is a revolution in firearms history, putting the ability of an electromagnetic pulse in a relatively small round. The power output is not extreme, but it is enough to rapidly take out a shielded enemy, and it is advised that, if available, every third, fourth, or fifth round be an EMP round.
However, this ammunition is generally only available to Special Forces.
====Armor-Piercing====
Due to the rising amounts of Covenant in the mid-2570s, an armor-piercing (AP) round was developed for the MA7 series. It is made out of depleted uranium with a tungsten-carbide core.
===9.5x40mm (.37 Caliber)===
The 9.5x40mm round was a full-power rifle round used with battle rifles, notably the BR55 and BR60 Battle Rifles, and medium machine guns such as the Type 47 Machine Gun. The 9.5x40mm KURZ round used a highly experimental chemical propellant (rumoured to be a plasma-based component derived from Covenant technology), meaning the round was able to produce a higher muzzle velocity than the 7.62x51mm NATO round, doing so with a smaller casing and a larger bullet. The round's increased velocity and weight considerably increased its kinetic energy, meaning that upon impact with a target it imparted a significant amount of energy. This, along with its accuracy and range contributed to its potency; it was effective against body armour and even energy shielding employed by Covenant infantry.
====M634 High-Powered Semi-Armour-Piercing====
The former standard round issued with 9.5mm calibre rifles, the M634 HP-SAP (or High-Powered Semi-Armour-Piercing) was largely superseded by more advanced rounds, especially for use with the modernised BR60 Battle Rifle. The round featured a lightweight ballistic cap, which deformed on impact with the target and offered superior aerodynamic properties to the projectile in flight. The bullet's exterior was composed of lead, which fragmented and expanded outwards upon impact with a target. The internal penetrator was comprised of tungsten carbide alloy; between this and the ballistic cap was a small space or 'hollow', into which the penetrator would force itself upon impact with the target (this also expanded and fragmented the bullet's lead jacket, causing expansive and grievous wounds). Later iterations of the round also featured a polymer which coated the bullet, acquiring an electric charge in flight and assisting in shield depletion.
====M635 Semi-Armour Piercing-High Explosive Incendiary====
The M635 Semi-Armour Piercing-High Explosive Incendiary, or SAP-HEI, was an ammunition type combining both an armour piercing and an explosive/incendiary capability. The bullet's tip was filled with a highly incendiary chemical, which burned at several thousand degrees upon impact with a target, damaging or melting armour and heavily affecting shields. Behind this was a high explosive component which detonated immediately on impact with a target, further damaging the area. Behind this was a solid core penetrator or depleted uranium, held in a backing 'cup' of steel. The components were held together in a copper or lead jacket. Upon hitting a target, the incendiary and explosive properties would damage the target area, aiding considerably in the depleted uranium's penetration into the interior. The penetrator featured a self-sharpening tip and was itself pyrophoric, meaning that it ignited upon impact with the incendiary material. It then punched through any remaining armour, having been ignited at this point and also carrying with it any remaining incendiary material from the tip. Effects on the target, especially if it was organically-based, were catastrophically damaging; the round would typically bypass any present armour (following rapid depletion of shields) and propel an incendiary penetrator and secondary incendiary material into the target's innards. Despite its effectiveness against a wide range of target types, it was highly expensive, meaning its cost limited its use. As a result it was normally employed only by special forces operators and select few ODST units.
====M636 Shield/Armour Piercing-High Explosive====
The M636 Shield/Armour Piercing-High Explosive, also known as S/AP-HE, was the most common and effective type of ammunition employed in the 9.5x40mm calibre. The bullet itself was coated in a polymer which acquired an electric charge while in flight, aiding the bullet's kinetic energy in depleting shielding and, although it had little effect on armour, giving an increase of about a third to the amount the bullet would drain a shield (assuming a distance of 500m). The further the bullet travelled in the air, the greater the charge it acquired, so this effect was at its most potent at longer ranges and nearly negligible at extreme close range.
The tip of the round consisted of a deforming ballistic cap; a lightweight element which crumpled upon impact with a target and gave the bullet superior aerodynamic characteristics. The bullet's armour-piercing core was a tungsten carbide penetrator with a self-sharpening tip; when it fractured upon impact, it would do so in a way that the remaining element was still a sharp point. The bullet's outer 'shell' was composed of hardened steel, which was webbed with prefragmented lines or weaknesses in the metal; the rear of the core penetrator was similarly fractured, and contained inside it a delayed timer fuze. A short amount of time after hitting a target and penetrating to its innards, the fuze would activate, blowing the penetrator apart along its stress lines, fracturing the external steel jacket and devastating the target's innards with white-hot metal fragments.
====M637 Jacketed Hollow Point====
M637 Jacketed Hollow Point (JHP) 
====M638 Tracer====
The M638 Tracer
====M639 Shield/Armour Piercing====
The M639 Shield/Armour Piercing (S/AP)
==Large Calibre Rifle Ammunition==
===11.4x90mm===
The 11.4x90mm round was a high calibre round designed for use in ranged anti-personnel weapons, though it did have limited usability in an anti-materiel capacity additionally. The round was designed as an intermediary between the 9.5x40mm battle rifle round, which did not have the ballistic characteristics qualifying it for this role (range, stopping power and accuracy) and the 12.7x99mm and 14.7x114mm rounds, which suffered from high recoil, resulted in less portable weapon systems and had ballistic qualities surplus to requirement. The round was used in successful weapons such as the M45A Marksman Rifle.
===12.7x99mm NATO===
The 12.7x99mm NATO round (colloquially known as the .50 cal or .50 BMG) is a large calibre round used predominantly in heavy machine guns and some anti-materiel rifles. The most notable usage of the round was with the M41 Light Anti-Aircraft Gun, although it was also used by the popular M60 Heavy Machine Gun. Offering better range, accuracy and kinetic energy upon impact with the target than the 11.4x90mm round, and lower recoil and increased ammunition capacity than the 14.5x114mm round, the .50 BMG was seen as a compromise between the two and hence was utilised in some lighter anti-materiel rounds and vehicle-mounted machine guns, such as the Sniper Rifle System-56M and the M247 Heavy Machine Gun respectively.
===14.5x114mm (.57 Caliber)===
The 14.5x114mm is the standard ammunition size for most of the UNSC's anti-matériel snipers and rifles, including the Sniper Rifle System 104 Anti-Matériel and the M90909 Javelin. The most popular anti-matériel round used by the UNSC, it is one of the most effective and lethal rounds produced in numbers for small arms, ensuring high accuracy, range and stopping power.
====Armor-Piercing Fin-Stabilized Discarding-Sabot====
The standard APFSDS round is incredibly useful against armored targets at extended ranges, capable of piercing tank armor and killing shielded enemies with one well-placed shot.
====Tracer Rounds====
The tracer round is a subsonic dart that has the ability to stick to armor. It acts as a GPS tag, allowing a scout to easily track the movements of enemy vehicles. A skilled operator can use it to track the movements of an entire armored block and feed the data to command.
==Shotgun Shells==
===8 Gauge===
The 8 Gauge shell was a powerful shotgun shell which provided extreme stopping power at close range. The shell was an unsually large calibre for military applications, being considered more powerful than necessary for most uses, though it was this that made it so effective against shielded and armoured Covenant at close range. Possessing high stopping power and decent range, the 8 Gauge's considerable recoil was often controlled by various weapon design techniques to allow it to be properly controlled and wielded effectively.
====M1056 Shot====
Alongside the M1059 Incendiary Flechette, the M1056 Shot Shell was the standard shell issued in the 8 Gauge calibre. The shell itself contained either 50 smaller or 20 larger spheres of tungsten carbide. Though actual spread varied according to the weapon itself, the shell generally possessed good range qualities. This was coupled with high stopping power, shield depleting and armour piercing characteristics, which meant that a single discharge could usually overcome all but the strongest adversary within its optimum range.
====M1057 Sabot====
The M1057 Sabot shell was a specially shaped, two-stage cartridge. It had an outer jacket that enabled it to travel further, outside a standard shot of 40 small spheres of tungsten carbide, or alternately 15 larger ones. The shell had a long range but relatively low penetration.
====M1058 Flechette====
M1058 Flechettes were similar to the M1057 Sabot, though replaced the shot with hundreds of tungsten carbide barbs or flechettes. These had high range and were usually deadly to armoured targets. The M1058 was in most respects superseded by the M1059.
====M1059 Incendiary Flechette====
The M1059 contained roughly 60 small, fin-stabilised armour piercing flechettes. These flechettes were composed of the depleted uranium and had indendiary, self-sharpening and pyrophoric properties. The flechettes had powerful armour-piercing ability and secondary incendiary effects to do high damage after initial contact with a target.
====M1060 Explosive Shot====
The M1060 Explosive Shot Shell was a standard shell filled with approximately 30 small explosive projectiles, utilising a powerful plasma-based explosive. Penetration was low, but actual power was high, especially against shielded targets; this resulted in their use being mainly tailored towards shielded enemies.
====M1061 Slug====
The M1061 Slug was essentially a crude rifle round, using a rifled, hollow slug consisting of a lightweight deforming ballistic cap and a steel exterior. Subtypes of this round include the M1061A Explosive Slug, which saw the hollow interior filled with a plasma-based explosive, the M1061B Armour Piercing Slug, which contained a tungsten carbide penetrator, and the M1061C Incendiary Slug, the interior of which was filled with an incendiary material.
==Grenades==
===40x53mm===
This ammunition type is also referred to as '40 millimetre', due to the round's diametre. The 40x53mm grenade is used by most grenade launchers including the MG460 Grenade Machine Gun. It was a high velocity grenade which made it more effective at both long and short ranges comparable to slower velocity, underslung launcher munitions. The round's increased speed resulted in a flatter ballistic trajectory, improving accuracy at range, while its increased velocity allowed it the ability to punch through unarmoured vehicle's skin (in addition to increasing range).
====High Explosive (HE)====
The standard 40 millimeter projectile. The projectile is filled with high explosive, which is detonated upon impact with an object or the ground.
====High Explosive Dual Purpose (HEDP)====
The High Explosive Dual Purpose (HEDP) was a dual purpose munition effective against both hard and soft targets. The round consisted of both a high explosive element and a surrounding fragmenting case, which made it effective against infantry and vehicular targets. Upon detonation the high explosive element would damage nearby fortifications and armoured targets, while the fragmenting case would severely damage most infantry. The grenade had a kill radius of about eight metres, and could injure targets out to thirty metres as a result of the fragmenting case. A direct hit to a light vehicle could generally destroy it outright, while better armoured targets such as tanks could take multiple hits.
====Flare====
A Flare projectile is a single slug of burning chemicals, appearing in red, green, or white coloring, depending on the . Each projectile casts brilliant light and intense heat without an explosion. These flares are used for signaling, illumination, or defensive countermeasures in military applications.
*M804F - Red
*M805F - Green
*M896F - White
==Magnetic Accelerator Cannon projectiles==
===25x130mm===
====Hyperdense kinetic penetrator====
Ammunition type fired by the M68 Asynchronous Linear-Induction Motor. It was designed to cause hypervelocity collisions, where the target and slug get almost entirely vaporized on impact. This was intended to reduce over-penetration, and risk of friendly fire. The ammunition is capable of being shot almost 16 kilometers, at a velocity of mach 40, with near-perfect accuracy.
==Shells==
===20x128mm===
The 20x128mm was a large calibre anti-materiel round used in some light autocannon, most notably the M3706 Autocannon. The round was deadly against infantry to an excessive degree, often reducing them to unidentifiable chunks as a result of sheer kinetic energy (even without secondary effects). As a result, although it could perform anti-personnel roles more than admirably, the round's primary usage was anti-vehicle and anti-air, where its stopping power and range, often coupled with rate of fire, made it formidable against lightly armoured aircraft and vehicles. A small number of anti-materiel rifles were chambered in the 20x128mm caliber, though the 14.7x114mm round was far more popular in this usage.
====M752 High-Powered Semi-Armour-Piercing====
The round featured a lightweight ballistic cap, which deformed on impact with the target and offered superior aerodynamic properties to the projectile in flight. The bullet's exterior was composed of lead, which fragmented and expanded outwards upon impact with a target. The internal penetrator was comprised of tungsten carbide alloy; between this and the ballistic cap was a small space or 'hollow', into which the penetrator would force itself upon impact with the target (this also expanded and fragmented the bullet's lead jacket, causing expansive and grievous wounds). Later iterations of the round also featured a polymer which coated the bullet, acquiring an electric charge in flight and assisting in shield depletion.
====M753 Semi-Armour Piercing-High Explosive Incendiary====
The M753 Semi-Armour Piercing-High Explosive Incendiary, or SAP-HEI, was an ammunition type combining both an armour piercing and an explosive/incendiary capability. The bullet's tip was filled with a highly incendiary chemical, which burned at several thousand degrees upon impact with a target, damaging or melting armour and heavily affecting shields. Behind this was a high explosive component which detonated immediately on impact with a target, further damaging the area. Behind this was a solid core penetrator or depleted uranium, held in a backing 'cup' of steel. The components were held together in a copper or lead jacket. Upon hitting a target, the incendiary and explosive properties would damage the target area, aiding considerably in the depleted uranium's penetration into the interior. The penetrator featured a self-sharpening tip and was itself pyrophoric, meaning that it ignited upon impact with the incendiary material. It then punched through any remaining armour, having been ignited at this point and also carrying with it any remaining incendiary material from the tip. Effects on the target, especially if it was organically-based, were catastrophically damaging; the round would typically bypass any present armour (following rapid depletion of shields) and propel an incendiary penetrator and secondary incendiary material into the target's innards. Despite its effectiveness against a wide range of target types, it was highly expensive, meaning its cost limited its use. As a result it was normally employed only by special forces operators and select few ODST units.
====M754 Shield/Armour Piercing-High Explosive====
The M754 Shield/Armour Piercing-High Explosive, also known as S/AP-HE, was the most common and effective type of ammunition employed in the 9.5x40mm calibre. The bullet itself was coated in a polymer which acquired an electric charge while in flight, aiding the bullet's kinetic energy in depleting shielding and, although it had little effect on armour, giving an increase of about a third to the amount the bullet would drain a shield (assuming a distance of 500m). The further the bullet travelled in the air, the greater the charge it acquired, so this effect was at its most potent at longer ranges and nearly negligible at extreme close range.
The tip of the round consisted of a deforming ballistic cap; a lightweight element which crumpled upon impact with a target and gave the bullet superior aerodynamic characteristics. The bullet's armour-piercing core was a tungsten carbide penetrator with a self-sharpening tip; when it fractured upon impact, it would do so in a way that the remaining element was still a sharp point. The bullet's outer 'shell' was composed of hardened steel, which was webbed with prefragmented lines or weaknesses in the metal; the rear of the core penetrator was similarly fractured, and contained inside it a delayed timer fuze. A short amount of time after hitting a target and penetrating to its innards, the fuze would activate, blowing the penetrator apart along its stress lines, fracturing the external steel jacket and devastating the target's innards with white-hot metal fragments.
====M6755 Tracer====
The M755 Tracer
===30mm===
===50mm===
===90mm===
===120mm===
===155mm===
====155mm HE Shell====
The standard 155mm high explosive shell is used for bombarding an area. It is not wholly accurate, but is perfect for destroying clustered formations and suppressing fire.
====155mm Cluster Shell====
The 155mm cluster shell extends the effective blast area of the standard HE shell. As the shell descends and approaches the ground, a proximity sensor causes the shell to split and spread a dozen warheads over an area.
====155mm Guided Munition====
The 155mm guided munition is a long-range projectile that is fired in to the air and, once it reaches max height, rotates and fires straight at a marked target. The target is generally marked by a designation laser by frontline troops.
Category:AAO Weapons