Welcome Tenno!
Here we talk about what primary weapons are the best to face any threat in Plains of Eidolon. What you need are weapons with high damage and a medium or long range, because you almost always be in the open field. These weapons will allow you to eliminate most enemies before the can return fire.
We talk about the weapons you can use against the Eidolon Teralyst in the final section of this entry, but keep in mind that there is no “perfect” weapon but there is an “ideal” strategy.
Primary Weapons
We have highlighted the following weapons for their destructiveness, sorted by their Mastery Rank requirements.
1. Hek
Required Mastery Rank: 4
This Grineer shotgun is capable of unleashing chaos and destruction even at long range. Its high damage makes it an excellent choice if what you want is to wipe out a Grineer camp. Its weak spots are its limited magazine capacity and its slow reload speed.

2. Opticor
Required Mastery Rank: 6

If you have ever dreamed of wielding a heavy weapon designed for space combat between towering ships, this is your weapon. A devastating cannon capable of piercing the thickest shields, reduced to a portable size. The great advantage of this weapon is the huge amount of damage it can cause, its high critical probability, its critical damage and its long range. Its weak spots are its small magazine, its slow reload and its low rate of fire.
3. Arca Plasmor
Required Mastery Rank: 10
This Corpus Shotgun based on Radiation damage can be a very good ally for multiple situations. Its high damage and critical probability will help you to take down enemies close to each other, as long as they are at medium range. Its weak spots are, as usual in most shotguns, its reload speed and its rate of fire.

4. Vaykor Hek
Required Mastery Rank: 12

This is Hek’s “elder sister”, with superior magazine and an enhanced critical probability and critical damage. Is a versatile option for its long range and perfect for its capability to take down almost everything with one shot. Ideal to accomplish the Bounties Konzu offers.
Recap
To sum up, among the weapons we mentioned, we can highlight the Opticor, the Plasmor Arca and the Vaykor Hek for their capability to eliminate practically any Grineer scum you find with one shot. Moreover, the Opticor would stand out between these three if you want to take down Grineer ships, being an adapted anti-aircraft gun it’s no surprise.
The Eidolon Teralyst Hunt
If your goal is to hunt the Eidolon Teralyst, the Opticor can be a very god choice, but not the only one. Any primary weapon with high damage and a build based in Radiation damage will help you to submit this powerful war machine.
The perfect combination is a weapon with high base damage and a high critical probability and damage, and a low status probability, because the Eidolon Teralyst can NOT be affected by status effects. A build based on Radiation damage (Heat + Electricity), is useful because when its shields are down you have to pierce its alloy armor and tear apart its Robotic body, being the radiation damage very effective against the armor and effective against the body.
Do you want to hunt the Eidolon Teralyst? Explore the Plains alone? Accomplish the Bounties faster? Here you will find which warframe is the best for each situation.
Draw your sidearm and gear up to go out to the Plains of Eidolon. These secondary weapons will give you an unparalleled tactical advantage out there, Tenno.
Although the Plains of Eidolon are huge, there will be moments when you have to get your hands dirty. Here you have the best weapons to unleash chaos in Eidolon.
We hope this information has been useful to you. Remember that this list can always be enlarged, and the final choice will always be yours. You have to be armed to the teeth, Tenno, but always with weapons that you know, suitable to your play style, and useful.
As always, if you find any mistake or missing information let us know through the comments below.
Good luck, Tenno.
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Lanka. 50% flat crit chance when zoomed and 100% radiation. Hardest hitting sniper of all the snipers. Add Deadeye and riven you’ll one shot every limb.
I use a Lanka with six formas and a riven on it , deals insane damage. As for my amp I have a 323 amp build and arcades on my warframe and operator. I have killed five teralysts and captured 11 and done one tridolon.
Opticor is MR 14……not 6.