Review: Arca Plasmor (U24.1.2)

The Arca Plasmor is an MR10 shotgun that fires single large waves of plasma, rather than multiple pellets. Relased in U21.7, it is a unique, rather powerful, but most importantly, very fun weapon that excels in the majority of Warframe's combat.

Acquisition

The Arca Plasmor must be researched at a Dojo's Energy Lab to acquire the blueprint.

Stats

The Arca Plasmor has extremely high base damage, with good Crit and Status Chances, but a frustratingly low Crit Damage. Its Fire Rate is also very slow, though this gives it a solid Reload Ratio of 3.25.

Notably for a shotgun, the Arca Plasmor fires a single large wave of plasma rather than multiple pellets, meaning that 100% Status Chance is not necessary for a good status build. On the other hand, this also means that it is not capable of applying a large number of procs. The outer wave has innate Punch Through, however the central ball does not. The plasma wave has a limited range of 30 metres, with damage fall-off occuring in the 10-20 metre range.

The Arca Plasmor does not deal double damage on headshots as most weapons do. Critical headshots will still benefit from an additional 2x multiplier, but will not receive the total 4x multiplier that regular weapons do.

Augments

None.

Builds

0-Forma:

With two native V polarities, there are a lot of options for a Forma-less Arca Plasmor build. This first one is a basic crit build, with high raw damage. Corrosive + Heat + Radiation is a very powerful combination, lacking only against Corpus shields. Blaze is a great mod whenever the +Heat is not a problem.

An alternative crit-based build has Hunter Munitions slotted in, with Viral as the elemental combo. Although the Arca Plasmor has innate Radiation and great Status Chance, its single pellet wave and low RoF mean that it is incapable of quickly stripping armour with Corrosive procs. In my testing and experience, a crit-based Hunter Munitions build is actually the most effective anti-armour build, as building for raw Corrosive + Radiation damage drops off a lot faster at higher levels. Although it has mediocre crit even with the crit mods, the Arca Plasmor's very high base damage means that any Slash proc it inflicts will do major damage.

If you're not running Hunter Munitions however, this raw damage build will actually achieve much higher damage than a crit build. Part of this is due to omitting Primed Point Blank and Primed Ravage, which reduce the effectiveness of Vicious Spread/Blaze and increase the effectiveness of a crit build respectively. Without Primed Ravage, a crit build is very underwhelming, primarily due to Shotgun crit mods being relatively terrible. Without Primed Point Blank, Vicious Spread and Blaze are both relatively more effective, since they both give +Damage.

Note however that Vicious Spread can cause plasma waves to fly wildly off course.

Other good mod options not shown include Shotgun Spazz to patch up the very low RoF, Chilling Reload for a bit more damage but notably a big Reload Time buff, and Fatal Acceleration for the increased Projectile Flight Speed. As a projectile shotgun with limited range, +Flight Speed increases not only the Arca Plasmor's projectile speed, but also the drop-off ranges, as well as its maximum range.

I find that extra Punch Through isn't necessary, because of how the Arca Plasmor projectile behaves with enemies and obstacles. So long as you be careful and ensure that the central ball will not collide with obstacles, the shot will travel just fine.

Recommended Setups: Viral + HM vs Grineer, Corrupted, Viral or Viral + Electric vs unarmoured Corpus, Radiation or Radiation + Toxin vs armoured Corpus, Corrosive + Heat vs Infested.

General Purpose 2-Forma:

With added V and - polarities, you can fit all of the Primed mods in comfortably, still with space for other good mods. With Primed Ravage and Primed Point Blank, a crit build will deal more damage than a non-crit build, especially on headshots. This build is again a fairly standard Corrosive + Heat raw damage build.

Personally, I really like +RoF on the Arca Plasmor, as it feels far too slow otherwise.

A Viral + HM setup of course works well also, this build using Chilling Reload for the +Reload Speed, as well as being able to fit Shotgun Spazz.

Recommended Setups: see above.

General Purpose 4-Forma:

Two more V polarities and you can fit in just about any mod besides a Riven. This pictured build is a standard Corrosive + Heat full damage build. There isn't anything special about this build besides allowing for more, higher drain mods.

Recommended Setups: see above.

My Builds:

Contrary to the majority of my HM builds, I've found Corrosive to be a lot more consistent and effective, primarily due to the unreliability of HM. Each pellet has only a 12.54% chance of inflicting a Slash proc. As such, Corrosive + Radiation has proven to be a much more reliable and consistent setup.

My Riven gives +Reload Speed and +Fire Rate, which are the two stats I was looking for for the Arca Plasmor. I find its stock reload and RoF much too slow, which the Riven patches up nicely. The +Multishot is just a bonus.

This is the conventional Viral + HM build.

This build is for use against Infested, or for general purpose use if I can ensure enemies will have little to no armour (e.g. ESO if running Saryn). It packs much more raw damage than the other two builds, but is lacking against heavy armour.

Combat Use and Summary

Firing a giant wave of plasma with innate Punch Through, the Arca Plasmor excels at wiping out crowds of enemies. A single shot, aimed slightly above the heads of enemies will pass through and damage them all, likely killing the majority of them at typical Warframe levels. A direct shot may cause the projectile to explode on the first enemy hit. The Arca Plasmor's Reload Ratio is fairly solid, though is less relevant given the unique projectile type.

In contrast, the Arca Plasmor is relatively less effective against high health single enemies. A significant part of this is due to not gaining the 2x damage multiplier on headshots that most other weapons gain. Compared to other shotguns, it deals relatively less Burst DPS so although it can deal with such enemies in a reasonable time, lags behind a lot of other shotguns.

This carries on to armoured enemies as well. Without Hunter Munitions, the Arca Plasmor has no timely manner of eliminating or bypassing enemy armour. Though it can proc Corrosive quite reliably, it cannot do so quickly or in large volume, and it cannot naturally proc Slash. As such, it relies entirely on brute-forcing with raw damage through armoured enemies, which drops off quite harshly at higher levels. Hunter Munitions helps significantly in this respect, as despite its relative unreliability, it still deals with armoured enemies faster than the Arca Plasmor would otherwise.

Something of note is that any enemies hit within 15 metres are inflicted with a guaranteed Impact proc, which given the Arca Plasmor's massive hitbox, makes subsequent headshots much easier and safer to achieve. Also worth noting is that using Zephyr's Turbulence with Jet Stream Augment can also significantly boost the Arca Plasmor's range, though I've found 30m to be plenty for most engagements anyway.

Overall, the Arca Plasmor is a fun and fairly powerful shotgun. It obliterates crowds with ease, but falls behind a little in single target damage, especially if the target has a lot of armour. Limited 30m range is generally not a problem in Warframe's largely close quarters combat. The Arca Plasmor is a weapon I strongly recommend building and trying out. It is extremely popular for very good reason, and can take out most Warframe content quite well, especially with some anti-armour support.

Scores

Vs Trash Mobs: 5/5 - A single shot can eat through an entire corridor worth of enemies. Its slow RoF can be frustrating for follow-up shots, but trash mobs rarely require more than one shot. Reload Ratio is also fairly good.
Vs Unarmoured Heavies: 3/5 - The Arca Plasmor has reasonably high damage-per-shot, but its low Fire Rate holds back its Burst DPS. Many other Shotguns deal significantly more single-target damage. The loss of headshot multiplier also hurts.
Vs Armoured Heavies without Hunter Munitions: 2.5/5 - With too low a RoF for rapid Corrosive proccing, and no Slash damage, the Arca Plasmor's only non-HM anti-armour is to brute force through with raw damage. It does ok at this thanks to base Radiation damage, but this drops off quickly at higher levels, especially without the headshot multiplier.
Vs Armoured Heavies with Hunter Munitions: 3/5 - Even with HM, a low RoF and mediocre Crit Chance even with Blunderbuss means that Slash procs are not especially frequent, and again lacking the headshot multiplier really hurts damage output.

Vs Variants

None.

Competitors

The only weapon remotely like the Arca Plasmor is the Catchmoon Kitgun, which is a secondary.

Rivens

The Arca Plasmor has a rather low 2/5 (0.7) Riven Disposition, being dropped from 3/5 in U24 with Fortuna (0.9 -> 0.7). This is reasonably fair given it is quite powerful and extremely popular, though I don't think such a large drop was necessary.

Damage/Multishot/Crit Chance/Crit Damage are of course great stats to aim for. I personally consider +Reload Speed and +Fire Rate to be fantastic as well. An appropriate element (e.g. +Toxin) can save a mod slot. Notably, +Projectile Flight Speed increases the range of the Arca Plasmor, so can also be good stat to have.

-Max Ammo is not a problem if you run Ammo Case/Mutation/etc. I would consider -Infested Damage to be pretty reasonable, as well as perhaps -Corpus Damage.