Armored Core 6: Fires of Rubicon Guide – Best Weapons and OS Upgrades, and All Core Expansions

Whether you're having trouble against bosses or trying to outfit your AC with the best equipment, here are the best weapons and upgrades.

Posted By | On 31st, Aug. 2023

Armored Core 6 Fires of Rubicon

Customizing a mech in Armored Core 6: Fires of Rubicon is like building a car. It seems like a good idea, but you must keep several things in mind. How fast do you want it to go? What kind of vertical lift are you looking at? How often will you be dodging, if at all? Trying to make sense of terms like AP (Attack Power), Weight, and more is also tough for those who want to sit down and blow up some mechs.

However, as the challenges mount, it’s good to know which weapons are strong and which are downright broken to the point of dispelling any sense of difficulty. There are also Core Expansion and OS Tuning Upgrades that you should pick up to maximize your efficiency.

Check out our recommendations for the best weapons and OS Tuning Upgrades in Armored Core 6: Fires of Rubicon, and which Core Expansion is worth using in what situation.

Best Weapons

HI-32: BU-TT/A (Pulse Blade)

Available at the very start of the game, the HI-32: BU-TT/A is a good melee weapon in almost every circumstance. It has 963 Attack Power, 720 Impact and can hit two times. The EN Load is only 213 while its Weight is 1800. Whether you’re looking to pile damage onto a staggered target or deal with some quick close-range attacks, it’s very reliable. Best of all, it’s free.

Vvc-774LS Laser Slicer

If you’re in New Game+ and want a stronger melee weapon, the Vvc-774LS Laser Slicer is worth a look. You can purchase it at the beginning of Chapter 4, and it’s the same weapon used by V.IV Rusty. It has 1615 Attack Power with 900 Impact and hits twice while weighing 3260 with 328 EN Load. You can also charge it for more damage, and the range is ridiculous. Ensure you’re close enough to land your strikes since the cooldown is rather long.

WR-0777 SWEET SIXTEEN (Shotgun)

One of the best shotguns in the game, the WR-0777 SWEET SIXTEEN is available in the Parts Shop for only 49,000 COAM. It has an Attack Power of 85 per pellet (with 13 per shot, so 1105 damage if they all land) and 61×13 Impact. There are 546 rounds, with the EN Load being 268 and Weight totaling 1640. While shotguns are best suited for close-range combat, pairing them with a lightweight AC works wonders, especially if you dual-wield shotguns.

VVC-70VPM (Plasma Missile Launcher)

The VVC-70VPM costs 96,000 COAM in the Parts Shop, but you must complete Destroy the Weaponized Mining Ship in Chapter 1 to unlock it. It fires three plasma missiles into the sky, which rain down on enemies – even if they don’t directly impact, they have a potent area of effect. Its Attack Power is 760 with 382 Impact and 240 Total Rounds. If you can somehow fit it (which isn’t too difficult, given its 3760 Weight), the damage and ability to stagger ACs are well worth it.

SONGBIRDS (Grenade Cannon)

Another obscenely heavy Back Unit is the Songbirds. The Grenade Cannon has 754×2 Attack Power and 754×2 Impact while carrying 42 rounds. The Direct Hit Adjustment isn’t too bad either at 140, making it worthwhile against staggered targets (though you want to use it for staggering them in the first place). If you can manage its 5500 Weight, it’s worth carrying along with faster-firing weapons.

VE-60SNA (Stun Needle Launcher)

Perhaps the best Back Unit in the game, the VE-60SNA is purchased for 283,000 COAM in the Parts Shop after finishing the mission Destroy the Ice Worm in Chapter 3. It fires electric needles that discharge with 1088 Attack Power and 907 Impact. You can only carry 30 rounds, and it has a Weight of 6150 with an 825 EN Load. Nevertheless, with its long range, ability to stun targets (coupled with an insane 225 Direct Hit Adjustment) and short reload, it almost feels like cheating.

DF-GA-08 HU-BEN (Gatling Gun)

Scratch that – this feels like cheating. The DF-GA-08 HU-BEN is the only Gatling Gun in the game and becomes available for 170,000 COAM in the Parts Shop after finishing Attack the Waypoint in Chapter 1. While its Attack Power and Impact are only 25 each, it has 1300 rounds in total with 11 Accumulative Impact. So long as you’re landing shots – which is easy if you dual-wield them and keep track of enemies – you’ll build up stagger quickly.

Even more hilarious is its 215 Direct Hit Adjustment. If you get a staggered target, the DF-GA-08 HU-BEN can melt them. At 5800 Weight and 425 EN Load, there isn’t much room for other options, but it’s well worth using for unleashing hails of bullets on enemies.

HML-G2 P19MLT-04 (Missile Launcher)

If you need a missile launcher that isn’t too heavy and isn’t Plasma, the HML-G2 P19MLT-04 warrants a look. Available in the Part Shop for 80,000 COAM, it fires four tracking missiles, each with 216 Attack Power and 175 Impact. It has 180 Rounds, which makes it good for longer missions, and a Weight of 3250. The EN Load is also pretty low at 165. With a 0.4-second lock time and 2500 Effective Range, it’s pretty for keeping away from enemies while pelting them from afar with reliable damage.

PB-033M Ashmead (Pile Bunker)

Do you want to drive an exploding steel pile into enemies a la Alteisen from Super Robot Wars? The PB-033M Ashmead is the ticket. It’s purchased for 185,000 COAM in the Parts Shop and has 1688 Attack Power with 1150 Impact. The kicker is that it can be charged, dealing a whopping 4630 Attack Power and 1800 Impact while having explosive properties. It’s absurdly powerful, though it weighs 4180 and requires some timing. Use it on a staggered opponent, and they’re unlikely to survive.

VP-66LH (Laser Handgun)

After finishing the Intermediate Support 2: “Reverse-Jointed ACs” mission in Training, the VP-66LH can be purchased for 92,000 COAM from the Parts Shop. It has 175 Attack Power and 95 Impact, but the appeal is its charging. This results in 175×6 Attack Power and 95×6 Impact. Charge time is 1.2 seconds with 315 cooling and 435 EN Load. However, for a weapon like this with 380 rounds and only 2800 Weight, the only downside is being unable to dual-wield it.

SG-027 ZIMMERMAN (Shotgun)

This is the other best shotgun in the game and potentially even better than the Gatling Gun when staggering enemies. It’s purchased from the Parts Shop for 115,000 and has 900 Attack Power with 840 Impact. The Accumulative Impact is 420, while its Direct Hit Adjustment is 205, allowing it to stagger and shred through targets. With 53 rounds total, 4400 Weight and a 242 EN Load, this is one of the best guns in the game.

FASAN/60E (Plasma Cannon)

Unlocked after completing the mission “Escape,” which is near the end of the game, the FASAN/60E is worth carrying into New Game+. It has 1308 Attack Power and 840 Impact, weighing 6270 with an EN Load of 882. While only carrying 39 rounds, you can equip it on both shoulders and its plasma shots deal area of effect damage. Best of all, shots can be charged for even more damage and AoE, making it a force to reckon with.

IA-C01W7 ML-Redshift (Coral Oscillator)

Coral Weapons are pretty strong, though they can take some time to obtain. The IA-C01W7 ML-Redshift is an example, as you need to complete The Arena mission Defeat D3: Classified Subject in the Arena. It’s only available in New Game++, which means playing through the game twice beforehand.

However, even if you’re not chasing the true ending, it’s well worth the trouble. Not only does it fire waves of light with each slash, but it can be charged to deal more damage while massively increasing the area of said waves. It has 727 Attack Power and 530 Impact, hits twice and only has 2200 Weight. The EN Load is high at 544, but considering everything else (including the 190 Direct Hit Adjustment), this is a solid melee weapon and deals serious damage.

IB-C03W2 WLT-101 (Coral Oscillator)

Another worthwhile Coral Oscillator can be obtained from Rank 15 of the Loghunt Program. You must obtain Combat Logs from different targets, a grind unto itself. However, it’s probably preferable to the ML-Redshift, with 1350 Attack Power, 960 Impact and 2030 Weight. The Direct Hit Adjustment is 210, making it an ideal means of following up on staggered enemies.

Though it only hits once, you can charge it to perform a wide-sweeping attack. The latter is slower, but if there several enemies are in front, it can decimate them at once. The Charged Attack Power is 1950 while Charged Impact is 1450. If you’re going through and completing all of the content, it’s worth picking up.

DF-ET-09 TAI-YANG-SHOU (Explosive Thrower)

The DF-ET-09 TAI-YANG-SHOU is a little interesting since it has a low effective range but serves as an explosive launcher. It’s available for 215,000 COAM in the Parts Shop and can only be equipped on the Left Arm, like a melee weapon.

It has 1142 Attack Power and 830 Impact with 20 Blast Radius. When fired, it unleashes a spread of explosives in an area in front. When charging it, the explosives are unleashed in a vertical spread (though the Attack Power doesn’t change). It carries 25 rounds in total and probably isn’t the best for ammo economy.

Nevertheless, it does work well when building stagger on enemies. Using it on a staggered foe is also worthwhile since it has 190 Direct Hit Adjustment. With 3790 Weight and a measly 160 EN Load, it’s an unconventional but interesting option for those who like their explosive damage.

Best Core Expansions

You’ll want to get used to fighting in the Arena since it awards OS Tuning or OST Chips. These are necessary to unlock Core Expansions, which are essential abilities you can activate to get a temporary boost. The Arena is unlocked after finishing the Retrieve Combat Logs or Investigate BAWS Arsenal No.2 missions, both available in Chapter 1. There are only four Core Expansions, but each has a unique purpose and stats that could be useful.

Assault Armor

Assault Armor will generate an AoE shockwave that damages enemies and destroys incoming enemy projectiles. It’s best for fights against multiple hostile ACs or those that rely on pelting you with missiles. The Blast Radius is 60 while the Effect Range is 200, and its stats include 1500 AP, 2000 Impact and 230 Direct Hit Adjustment (which means more damage dealt to staggered enemies). Requires one OST Chip to unlock.

Pulse Armor

Generates a barrier that follows you, increasing Resilience by 3300 for 10 seconds. It will go away when taking enough damage as well. Requires two OST Chips to unlock. While it can be used to distance yourself from enemies, it’s also not bad as an offensive tool. Tank damage from an enemy using the barrier and then get in close with shotguns, pulse sabers and more to inflict massive damage.

Pulse Protection

Similar to Pulse Armor, except it creates a barrier in a fixed spot, which has 4000 Resilience and lasts 25 seconds. It’s perhaps your best ranged defensive tool, as it provides a point to fight around while you assail an enemy with projectiles. It requires three OST Chips to unlock.

Terminal Armor

More of an emergency defense tool, Terminal Armor offers 20,000 Resilience but for only two seconds. It could be a last-ditch effort to get damage in or to offset massive amounts of damage from a particular enemy. Of course, you shouldn’t lean on it too much. Requires five OST Chips to unlock.

Best OS Tuning Abilities

OS Tuning is divided into several categories, from abilities to use in combat to passives that increase outgoing damage. Your mileage may vary for some of them based on your current build – like increased Kinetic damage in place of more Energy damage – but they’re all worth using. If you don’t like a particular unlock, you can always respec, though the cost will increase with each respec.

Boost Kick

Requires one OST Chip, Boost Kick is essentially a high-powered kick. Combined with your AC’s Weight and Assault Boost, it can cause significant damage. It’s also an additional hit when using melee weapons or to knock back lighter enemies.

Weapon Bay

Weapon Bay is the ticket for those who don’t want to use missile launchers or other shoulder-mounted weapons. It allows for using weapons ordinarily reserved for the hands on your shoulders. Is it a good idea to use four Gatling Guns? Probably not, given the Weight (though there is a way around it), but it’s a fun novelty nonetheless. Unlock it with two OST Chips.

Weight Control

When the player’s AC is overburdened, they can’t go on missions. Weight Control removes that, allowing you to Sortie, but also providing the option to purge weapons during missions. Your Weight decreases and speed increases in the process. So you could theoretically carry more weapons when taking out trash enemies, then purge them to increase speed when going up against a boss.

Even if you’re not interested in overburdening your AC, purging weapons is ideal for lightweight, double-shotgun builds since you won’t have to sacrifice too many defenses for speed. Purge your shoulder weapons, and you’re good to go (though if you want to spec into Kinetic and Energy damage instead, that also works). Requires three OST Chips to unlock.

Quick Turn

As the name indicates, Quick Turn allows for executing quicker turns. When first starting, Armored Core 6’s turning and momentum can take some time to adjust to. If you want to turn on a dime faster, then Quick Turn should help, and it’s only one OST Chip.

Kinetic Weapons – Fire Control Tuning

This Attack Control upgrade increases the damage of all Kinetic weapons. Melee weapons don’t count, sadly. If you rely on assault rifles, Gatling Guns and whatnot, it’s worth getting and only costs two OST Chips.

Explosive Weapons – Fuse Control Tuning

This Attack Control Upgrade increases explosive damage (melee weapons not included) for two OST Chips. You’ll rely on shoulder-mounted missile launchers in the early going, so get this. Once more options become available, you can unspec this.

Energy Weapons – Output Control Tuning

Increases all energy damage, not including melee weapons, for two OST Chips. When you unlock more energy weapons throughout the campaign, including those that can be charged for massive damage, this upgrade will become vital.

Melee Weapons – Drive Control Tuning

Melee weapons are very high risk, high rewards, especially as the campaign wears on. Nevertheless, if you like it for the obscene amount of damage it deals up close (especially to staggered enemies), this Attack Control Upgrade is worth it, increasing melee damage for all sources. It costs three OST Chips.

Direct Hit Modifier – Damage Tuning

Given how important stagger is, dealing more damage to staggered targets is always good. You’ll want to pick up this Attack Control Upgrade since it increases the damage of direct hits against staggered enemies. It costs four OST Chips to unlock.

ACS – Dynamic Deflection Control Tuning

If you feel a bit too squishy, especially in the early going, this Damage Control Upgrade might help. It reduces damage received from enemies and costs two OST Chips.

Repair Kits – Optimization

This is another strong Damage Control Upgrade, especially in prolonged fights, which boosts the healing provided by Repair Kits. For only three OST Chips, it’s worth having, especially when piloting a lighter AC that can take a lot of damage.

Armored Core 6: Fires of Rubicon is available for Xbox One, Xbox Series X/S, PS4, PS5 and PC. You can read our official review here. If you want to know some strong builds, head here and here for a list of all the other parts to customize your Armored Core with and their requirements. For taking down a specific boss, you can read our guide here.

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