Gunbreaker Tank Advanced Optimization Guide — Dawntrail 7.4

Recent changes have invalidated what was in this rotation section previously, and it has been moved into the Tank Rotation page.

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.

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)
Keen Edge	Weaponskill	0.89
Brutal Shell	Weaponskill	1.07
Solid Barrel	Weaponskill	1.65
Burst Strike	Weaponskill	0.71
Hypervelocity	Ability	0.76
Gnashing Fang	Weaponskill	0.62
Jugular Rip	Ability	0.80
Savage Claw	Weaponskill	0.62
Abdomen Tear	Ability	0.76
Wicked Talon	Weaponskill	1.16
Eye Gouge	Ability	0.98
Double Down	Weaponskill	0.72
Sonic Break	Weaponskill	0.62
Bow Shock	Ability	0.62
Blasting Zone	Ability	0.62
Lightning Shot	Weaponskill	0.72
Reign of Beasts	Weaponskill	1.16
Noble Blood	Weaponskill	1.65
Lion Heart	Weaponskill	1.79
Demon Slice	Weaponskill	0.62
Demon Slaughter	Weaponskill	0.62
Fated Circle	Weaponskill	0.54
Fated Brand	Ability	1.16