Hello there,

As per Wiki:

• Kuva Grattler: No longer auto-spool; reaches peak fire rate instantly.
• The weapon's max rank caps at 40 after 5 polarizations - max rank increases by 2 per Forma added (similarly as the Paracesis).
• All Kuva weapons deal innate elemental damage in addition to physical damage. The amount of this damage is random, ranging from 25-60%, while the type of element is determined by the Progenitor Warframe, as per the table below:

According to the above, I added exactly 5 forma to this weapon, so we can obtain Mastery Points from it.

In this case, I recommend picking Magnetic as an elemental. Why? For free combined elemental. So why not "Radiation" instead? Well because Radiation make shiet damage. And Magnetic is free damage against Corpus shields.

Let us check what this heavy caliber got:

• High accuracy.
• Shots explode in a 9-meter radius upon impact with a surface or enemy.
• Initial hit and explosion apply status separately.
• Explosion does not need direct line of sight to deal damage and will penetrate walls.
• Projectiles have travel time.
• Explosions inflict self-stagger.
• Explosion has linear damage falloff from 100% to 30% from central impact.

Archwing:

• Slowest reload speed of all arch-guns.

Atmospheric:

• Linear damage falloff from 100% to ?% from 100m to 350m target distance in atmosphere (distances are affected by Projectile Speed).
• Projectiles have a maximum range of 350 meters.
• Poor ammo efficiency, generating high cooldown for the Archgun Deployer for every second fired.

My advice? Use it with Dispensary skill. You will never run out of ammo.
Amazing AoE heavy solution for heavy problems. I love this weapon. Reload could be a bit faster tho.

Enjoy! THeMooN85