Gunbreaker Tank Advanced Optimization Guide — Dawntrail 7.2
On this page, you will find information regarding advanced techniques and optimization geared towards Gunbreaker. The information presented is not for beginners and may include intermediate math or non-standard rotational changes.
Introduction to Advanced Gunbreaker Techniques
Credit for this information must be given to Krom, Azazel, Aletin, Kyo, and the rest of The Balance's Gunbreaker team for theorycrafting and fact checking this information.
The following sections assume that the reader has read and understands how the basic GNB rotation works, and therefore will not be going over the basics of the rotation. Please refer back to the standard Gunbreaker Rotation Guide if you are not familiar with the basics.
Standard 2.50 Gunbreaker Opener

Due to the fact that 2.50 can only fit eight GCDs inside of No Mercy,
there is no room for error whatsoever when fitting GCDs inside the buff when
Bloodfest
is available. The
Gnashing Fang combo,
Lion Heart combo,
Double Down, and
Sonic Break add up to a total of eight GCDs.
The Keen Brutal No Mercy opener fits these skills inside of
No Mercy, while also
aligning with standardized raid buff timings as much as possible for maximum potency in party buffs.
An additional benefit to this opener is that it forces a "0/2 (Zero-Two) Loop", providing a bit of extra potency by
allowing for
Hypervelocity to be inside the
No Mercy buff three out of every four windows.
This loop will be explained in detail in a later section.
2.50 Rotation Priorities
After the opener and between No Mercy windows, continue the rotation with the following filler priorities:
- Use
Gnashing Fang combo and
Blasting Zone as soon as they are ready. Ensure you have a Cartridge to use
Gnashing Fang immediately!
- Use
Burst Strike to avoid overcapping Cartridges.
- Use the
Solid Barrel combo to generate Cartridges.
No Mercy should be used as soon as it is ready, and this should result in it
being early-weaved every time it is ready.
Aim to have three cartridges on odd minutes. During odd minute No Mercy windows, use the follow priorities under the buff:
- Use
Double Down,
Gnashing Fang,
Blasting Zone, and
Bow Shock as soon as they are ready.
- Finish the rest of the
No Mercy window with
Burst Strike with any remaining cartridges, and
Solid Barrel combo GCDs otherwise.
During even minute No Mercy windows, use the following priorities under the buff:
Burst Strike before entering
No Mercy, then weave
No Mercy followed by
Hypervelocity to get some extra potency in the buff.
- Use
Double Down,
Gnashing Fang,
Blasting Zone,
Bow Shock, and
Bloodfest as soon as they are ready.
Bloodfest should be used after
Double Down.
- Use
Sonic Break after
Double Down. This will mirror where it was used in the opener.
- Finish the
Gnashing Fang combo, then use the entire
Lion Heart combo inside of
No Mercy's buff.
Mitigations and How They Stack
All mitigation in FFXIV interacts multiplicatively, like all other buffs in the game. However, perhaps
counterintuitively, mitigation stacking gives less than the sum of the individual mitigations used.
For example, using Heart of Corundum does not give 30% mitigation for 4 seconds.
Instead, it gives 15% * 15% mitigation for 4 seconds, which equals out to 28% mitigation for the first
4 seconds, and 15% mitigation for the final 4 seconds. This is because the way the game calculates the
mitigation in is terms of %damage taken by the player.
This formula is always represented as 100 * (1-mitigation value as a decimal),
repeating the * (1-mitigation value) for each individual mitigation source.
Using Heart of Corundum again as an example, the damage formula would be calculated as
100 * (1-0.15) * (1-0.15) = 72. This means the player takes 72% of incoming damage,
which is the same as saying 28% mitigation, instead of 70% damage taken or 30% mitigation as some might expect.
This effect is even more noticeable when stacking multiple mitigations.
Heart of Corundum,
Rampart, and
Great Nebula when used at
the same time do not equal 70% mitigation. Instead we again use the damage taken formula of 100 * (1-0.15) * (1-0.15)
* (1-0.40) * (1-0.20) = ~34% damage taken, or 66% mitigation. Please note that it is not exactly 34%/66%, as there is some
rounding that the game systems do on the backend. However, this is good enough for explanation of how mitigation interacts.
Application Delay
All abilities have some time between when they start their ability clock and when they actually apply the damage.
This is called application delay. This delay can be extremely important to know because there are
situations where using a higher potency ability on paper is a loss because it ghosts, or in other
words the damage does not apply before the target becomes invulnerable due to fight phasing or the target dies.
Please note that application delay does not have any effect on whether an ability
retains a buff or not. Buffs are snapshot when the cooldown clock begins to spin for instant
cast abilities. Especially in the case of Gunbreaker having some abilities with fairly long application delays,
it is possible for an ability such as Solid Barrel to be used with the
No Mercy
buff still active, the buff expires, and then the damage applies. Because the buff was present for the snapshot, the
damage will be buffed despite being applied after the buff expired.
Below is a list of Gunbreaker application delays. For abilities that apply a buff, such as
No Mercy or
Great Nebula, the time between the skill activating and the buff
applying is between 0.5 and 0.6 seconds on average.
Skill Name | Type | Delay Length (in seconds) |
---|---|---|
![]() |
Weaponskill | 0.89 |
![]() |
Weaponskill | 1.07 |
![]() |
Weaponskill | 1.65 |
![]() |
Weaponskill | 0.71 |
![]() |
Ability | 0.76 |
![]() |
Weaponskill | 0.62 |
![]() |
Ability | 0.80 |
![]() |
Weaponskill | 0.62 |
![]() |
Ability | 0.76 |
![]() |
Weaponskill | 1.16 |
![]() |
Ability | 0.98 |
![]() |
Weaponskill | 0.72 |
![]() |
Weaponskill | 0.62 |
![]() |
Ability | 0.62 |
![]() |
Ability | 0.62 |
![]() |
Weaponskill | 0.72 |
![]() |
Weaponskill | 1.16 |
![]() |
Weaponskill | 1.65 |
![]() |
Weaponskill | 1.79 |
![]() |
Weaponskill | 0.62 |
![]() |
Weaponskill | 0.62 |
![]() |
Weaponskill | 0.54 |
![]() |
Ability | 1.16 |
Guides from Other Classes

Torael Valdis, or Tor for short, is an experienced raider in FFXIV who has been playing the game since the tail end of the Heavensward expansion. His experience includes multiple Week 1 Savage Tier kills as well as completion of each Ultimate Raid in the patch they were released. You can find him in The Balance Discord where he currently is active as a melee DPS mentor. He also occasionally streams early prog on his Twitch.
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