Best Rubico Prime Eidolon Build – 2021

Best Rubico Prime Eidolon Build Warframe

Best Rubico Prime Eidolon Build – 2021

If you’re looking for the best sniper to hunt Eidolons, you’ve come to the right place. The Rubico Prime shines through insane critical stats, the single best zoom bonus and awesome attack speed. Especially when build with this Rubico Prime Eidolon Build, you will take down every Eidolon’s limb in a matter of seconds.

I have slightly updated the build on September 7, 2021 as a reaction to the recent weapon balance chances.


  1. Rubico Prime Eidolon Build Requirements
  2. Rubico Prime Eidolon Build Modding
    1. Rubico Prime’s Critical Stats & Damage
    2. Radiation Damage against Eidolons
    3. Primed Cryo Rounds
    4. Exilus Mod
  3. Rubico Prime Sniper Combo and Zoom Mechanic Explained
    1. Combo Counter on Snipers
    2. Zoom Bonus on Snipers
  4. Conclusion: Best Rubico Prime Eidolon Build – 2021

Rubico Prime Eidolon Build Requirements

  • Orokin Catalyst
  • 5 Forma
  • Exilus Adapter

Rubico Prime Eidolon Build Modding

Rubico Prime Eidolon Build Warframe

Rubico Prime’s Critical Stats & Damage

Vital Sense for Rubico Prime Eidolon Build

As already teased, the Rubico Prime has some great critical stats. In fact, they are the best of all sniper rifles in the game! To make use of this, we are using Vital Sense and Critical Delay for critical damage and chance. This leads to an awesome 114% critical chance and 6,6x critical damage!

Then, there’s Serration and Heavy Caliber for obvious reasons and Split Chamber for multishot. These mods are a simple yet potent way to increase our damage output with our Rubico Prime Eidolon Build.

Radiation Damage against Eidolons

Radiation Damage Warframe

Next up, there are the three elemental mods: Stormbringer, Hellfire and Primed Cryo Rounds. Starting with Stormbringer and Hellfire, their Electricity and Heat damage combine into Radiation. Why do we specifically want Radiation damage, though? Well, every Eidolon has armor as you may have noticed and not just any kind. It is Alloy Armor. If you aren’t familiar with how different armor and also health and shield types work in Warframe, each of them has strengths and weaknesses against specific damage types. To stick with our situation, targets equipped with Alloy Armor will take 50% less damage from Slash but 75% bonus damage from Radiation, for example. As a result, we mod for Radiation damage.

Related: Damage Types Guide

Primed Cryo Rounds

Primed Cryo Rounds for Rubico Prime Eidolon Build

As for Primed Cryo Rounds, it is our second, better Heavy Caliber. Both provide 165% bonus damage but Primed Cryo Rounds comes without the negative 55% Accuracy that Heavy Caliber suffers from. On top of that, Primed Cryo Rounds doesn’t increase our physical damage but adds Cold. That’s great because most of our physical one is Impact damage which has neither an increase nor a decrease against the Eidolons’ Alloy Armor. Cold damage, on the other hand, gets a 25% bonus! Of course, some of you might not have this Primed mod in which case I suggest Vigilante Armaments for some more multishot.

Exilus Mod

Ambush Optics Rubico Prime Exilus Mod

Lastly, the Exilus Slot mostly comes down to personal preference as it usually does. I like Vigilante Armaments as it is the only Exilus mod that can even slightly increase your DPS thanks to the set bonus. Still, it’s only 0.8% as you can see so it doesn’t really matter if we are being honest. Ambush Optics is another great choice as you’re mostly quite close to the Eidolon and the zoom can often hinder at that range. Unless you don’t max these mods you will have to add another Forma, though. If you do not have a problem with any of that, feel free to use any other mod.

Rubico Prime Sniper Combo and Zoom Mechanic Explained

Combo Counter on Snipers

Now, let’s talk a little bit about the Combo Mechanic of snipers and especially the Rubico Prime. As you probably know, there’s a Combo mechanic in melee weapons based around your Combo counter which is increased by hitting enemies. A lot lesser known is the Combo mechanic of snipers. It works similarly as it still requires you to hit enemies in a short time frame to build up and not lose it, though it is much more unique to the sniper rifle you are using.You don’t need mods to make use of your Combo like melee weapons do but rather gain a damage bonus after a specific amount of hits depending on your sniper.

The Rubico Prime, for one, increases your damage by 50% on the first hit, already. For comparison, the Vectis Prime needs 5 hits for that and has a much lower magazine size and fire rate. By the way, multiple hits from multishot count towards our combo counter, too. That adds another point to the list of why Rubico Prime is the best sniper for hunting Eidolons in 2021.

Here’s a table from the wiki showing how many shots you need for every combo tier:

Warframe Sniper Combo Counter

Zoom Bonus on Snipers

As you might have heard already, Snipers also gain a special bonus when zooming in. This bonus is, again, very unique to each rifle and as a little teaser: Rubico Prime’s zoom bonus is one of the best.

On the first zoom-level (2.5x) you gain an additional 35% critical multiplier, while the second level (5x) grants a whole 50%! To compare this to the Vectis Prime, it receives 60% bonus headshot damage on the highest zoom. With the exceptional critical stats of our Rubico Prime Eidolon Build, extra critical multiplier isn’t only the best stat we could possibly receive but the Vectis’ headshot damage can only be used against Eidolons in the very last stage as their limbs do not have a “head”. Logo

Conclusion: Best Rubico Prime Eidolon Build – 2021

To wrap this thing up, try to stay zoomed in for your sweet critical multiplier bonus and you will have no problem taking down any Eidolon with this damage-packed Rubico Prime Eidolon Build. While it requires a respectable amount of Forma, the Rubico Prime deserves nothing less as it is truly the best weapon to take down Eidolons!

Thanks for reading!


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