MA5B assault rifle

The MA5B Individual Combat Weapon System was an assault rifle used by the UNSC Marine Corps and Navy throughout most of the Human-Covenant War. It was easily one of the most recognizable and pervasive infantry weapons fielded by the UNSC during conflict with the. The MA5B perfected and refined the defining features of the rifles introduced by the original MA5, such as the electronic ammunition counter and electronics suite, while also introducing new features like internal attachments and a larger, redesigned magazine. The massive success of the MA5B would lead to an even more successful weapon which debuted at the very end of the war: the MA5C.

Developement
The MA5B ICWS was commissioned by the UNSC just following the in the, which included the uprising that resulted in the  in 2492, and the  in 2494. Fearing the worst, the UNSC commissioned a number of weapons in order to update its aging arsenal in preparation for the possibility of civil war.

Misriah Armory and a handful of other weapons designers quickly churned out a number of prototype weapons. While most were quickly turned down, there were several that showed promise, including XM392A2, The XM55, the XMA25A1, the XM90A and the XSRS-99 Series 2. The XMA25A1 proved to be a hit amongst the marines who demonstrated the weapons, but most stated they disliked the designation, which they found to be a mouthful. Misriah Armory responded to this by making the decision to redesignate the rifle the XMA5B, and similarly renamed the XM55 the as well.

The newly christened XMA5B was a heavily revamped version of Misriah's MA5 assault rifle that was adopted by the in 2437. The weapon built further upon the principles that led to the success of the original MA5; ruggedness, versatility, and vicious medium-to-close-range firepower. Thanks to remarkably few setbacks in the rest of the development process, the finalized model of the XMA5B, now the MA5B Individual Combat Weapon System, was finished in record time, and in 2506 the UNSC Marine Corps adopted the MA5B to replace the MA5 as their primary service rifle, with the UNSC Navy following suit in 2514. However, the and  opted to keep fielding the original MA5 (known as the MA37 by the Army), since it was cheaper, still highly effective, and still receiving ongoing manufacturer support from Misriah.

Design Details
The MA5B was a marked improvement over the original MA5 rifle. The operation of the weapon was almost the same as the original MA5, though the reloading and locking process was made faster and more efficient, allowing for increased rate of fire, and the barrel was given very slight sound-suppressing properties to decrease the volume of the sound made when firing the weapon. The latter change was made to lessen the chances of the weapon's operator suffering hearing loss, which was a relatively common issue with the original MA5, as it was exceptionally loud. Unfortunately, Misriah overlooked one major issue with the MA5: suboptimal barrel twist. The barrel twist was 1 in 5.75, which was a poor choice for the weapon's caliber, as most other rifles chambered for a 7.62x51mm cartridge used at least a 1 in 10 twist. This resulted in the weapon being highly inaccurate at longer ranges.

The MA5B also featured a lightweight weather-resistant casing made from a stamped aluminum-based alloy and a heavy-duty plastic polymer. Another new feature was an internal attachment system; the heavy duty flashlight below the barrel could be removed and attachments such as underslung shotguns or grenade launchers could be affixed to the inside of the weapon, and could be done so with little difficulty and even in the field thanks to a small field-stripping toolkit located within the front end of the barrel shroud.

The electronics suite on the MA5B, unlike most UNSC weapons, included much more than just a wireless uplink that uploaded an aiming reticle into the user's vision via or into any visual displays that the operator may have been equipped with, but it also included an integrated ammunition counter, digital clock (which synchronized with the operator's neural interface upon activation of the weapon's electronics to ensure accuracy, and could be set to synchronize with other equipment the operator may have possessed if they did not have a neural interface or if their neural interface was not properly functioning), and a rudimentary digital compass. The weapon also featured retractable iron sights intended for use by non-UNSC users, who often lacked a device to upload a reticle into.

Ammunition
The MA5B was chambered for the UNSC's standard rifle cartridge, the M118 7.62x51mm AP-FMJ round. The 7.62x51mm round had historically been considered by most to be a full-power rifle cartridge, advances in antiballistic armor eventually made lower caliber rifle cartridges like the 5.56x45mm round obsolete. This caused the 7.62x51mm round to be downgraded into a gray area somewhere between a low-power and a full-power rifle cartridge. Therefore, based on their performance, weapons like the MA5B could be considered assault rifles while weapons like the could be considered battle rifles, despite being chambered in the same caliber.

Aside from standard armor-piercing rounds, the MA5B could also fire a number of specialized cartridges. One such cartridge was the, known more formally as the M149 .308 Soft-Jacket Fragmentation cartridge. The shredder round consisted of a bullet composed of numerous interlocking pieces linked to a weighted core by thin wire, which was coated in a soft metal shell. When fired into a material of sufficient density, such as flesh, the soft metal shell would tear open, the bullet would break apart, and the weighted core would penetrate the material and drag a number of sharp, irregularly-shaped metal bits in with it. Shredder rounds reduced the chances overpenetration while maximizing stopping power, but they were also only effective against lightly armored personnel. was able to use shredder rounds to great effect against a horde of frenzied during the  in 2535.

Aside from shredder rounds, the MA5B was capable of firing a number of firing a number of flechette rounds, nonlethal cartridges, and other non-standard ammunition types.

Advantages
The MA5B was an incredibly effective weapon against the Insurrectionists. Its brutal firepower and ferocious rate of fire could tear through lightly armored targets with ease, and its 60-round magazine meant that numerous enemies could be neutralized off of a single reload.

Against Covenant troops, the MA5B was less effective, but it still performed quite admirably. Less protected foes like Grunts or were easily shredded by the hail of bullets that the MA5B was capable of unleashing, however, Covenant troops equipped with  such as  could often shake off fire taken from an MA5B at range without trouble, thus weapons like the M392 DMR or the  were considered more ideal for engaging shielded enemies due to their superior accuracy. But the MA5B was found to be surprisingly accurate when fired in short, controlled bursts, and quickly developed a simple method to effectively engage Elites with the MA5B at most ranges: "pulsing" the trigger to release quick, accurate bursts of fire while drawing in closer to the alien, then opening up with fully automatic fire once up close, as an Elite's energy shielding usually could not withstand more than a few short moments of continuous close-range fire from the MA5B.

The MA5B's relatively poor performance against shielded targets while at range would continue to be an issue throughout the Human-Covenant War, but the SPARTANs' method of dealing with the issue became adopted as the standard tactic for engaging shielded enemies with the MA5B, and additional tactics for engaging shielded foes effectively with the weapon were developed over time as well.

In situations in which accuracy was secondary to rate of fire, the MA5B was second to none amongst the UNSCDF's small arms arsenal. Even the paled in comparison to the MA5B, as the M7's higher rate of fire was overshadowed by the MA5B's more manageable recoil and greater stopping power.

The MA5B was also one of the most durable infantry weapons fielded by the UNSCDF. The MA5B could be submerged in mud, then taken out and fired without issues and without having to clean the weapon, similar to the infamous AK-47 of the 20th century. The MA5B fared far better in harsh conditions than the much more tempermental M392 DMR or BR55, leading to it being heavily favored by Marine Special Forces, including and the Hostile Environment & Hazardous Operations Group. The SPARTAN-II supersoldiers also often used the MA5B as their weapon of choice, as they trained heavily with the weapon, and most of them were issued one of their own.

Disadvantages
As mentioned above, the MA5B's poor accuracy at range was its primary drawback. Even with a number of methods of compensating for this being available, using the MA5B at range still often resulted in a considerable quantity of ammunition being wasted. Due to this, Marines still often only used the MA5B at longer ranges as a last resort.

Aside from that glaring weakness, the MA5B had a number of smaller issues as well. One such issue was the fact that firing the weapon continuously for extended periods would over time cause residue to build up inside of the barrel near the bolt, further hindering the weapon's accuracy and increasing the possibility of a jam occurring (though the MA5B rarely jammed to begin with, so this was not all that much of a worry). In more severe cases this would result in an incomplete discharge (also known as a "squib load"), often causing the barrel to rupture if successive rounds were fired. Thankfully, this problem was easily prevented by limiting the use of fully automatic fire and cleaning the weapon routinely.

As time went on and the UNSC's MA5B arsenal began to age, another design flaw reared its ugly head. When the MA5B was fully loaded, the large quantity of rounds packed into the weapon's box magazine put a considerable amount of stress on the internal magazine spring. If magazines were left loaded for long periods of time, the spring would begin to plastically deform, meaning that when the rounds were removed from the magazine the spring would no longer deform elastically back into its original uncompressed state. This meant that the internal magazine spring was no longer able to push every round into the MA5B's receiver, resulting in failure to feed malfunctions. Though frustrating, the problem was relatively easily corrected by replacing the internal magazine spring or by simply using an entirely different magazine altogether. Still, later MA5 models reverted back to 32-round magazines in order to avoid the issue altogether.

MA5K Universale Kommando Karabiner
In the mid 2530s, commissioned a replacement for the MA2B. Misriah Armory subsidiary Heckler & Koch set to work creating an improved carbine variation of the MA5B, scrapping the MA2B's design entirely. The result of their efforts was the MA5K Universale Kommando Karabiner, which was paradoxially both more compact and more accurate than the MA2B. The MA5K was a massive hit amongst UNSC special warfare units, and the MA2B was completely phased out in favor of the MA5K by 2543.

UNSC Remarks
"Sometimes the rookies like to say that the MA5B is too weak, but everyone just laughs at them. Sure, the DMR will cut up a Split Lip or from a ways, but try keepin' yer wits about ya well enough to stop one of those foxtrots with it when they're breathin' right down yer goddamn throat! That's somethin' I've only seen SPARTANs do, and, well, not many of us are goddamn human tanks, now are we? The MA5B will send anything short of a down in a bloody heap in couple of seconds."

- An anonymous UNSC Marine Corps NCO.

"There are some marines who you just never see without their rifles. If you didn't know any better, you'd think they sleep with 'em, if you know what I mean, heh heh."

- An anonymous UNSC marine.

"When those damn Covie foxtrots attacked in '25 or '26, some guys were nervous about fighting them. Not me, though. I knew that not even the Devil himself could stand up against me and my assault rifle."

- An anonymous ODST.

"If you're using the MA5B up close, keep your mouth closed. That damn gun just chews shit up like you would not believe. Blood, guts, skin, fat, muscle, and bone; it all comes flying out at you. It's also a good idea to be wearing eye protection; a buddy of mine lost an eye when a bone fragment flew up and hit the poor bastard square in the face."

- An Anonymous UNSC Marine.