Gunbreaker Tank Advanced Optimization Guide — Dawntrail 7.1

Before talking about 2.50 GCD Gunbreaker, a disclaimer must be made. 2.50 Gunbreaker is extremely restrictive and strict. A single mistake can cost significant amounts of potency. This is not a prog friendly speed, nor is this speed recommended for someone who is just learning Gunbreaker for the first time. If this is not a concern for you, then keep reading to learn about the 2.50 rotation. If, however, this is a concern for you, the 2.40-2.47 rotation is much more forgiving and prog friendly.

Next, 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.

With those out of the way, lets jump into the 2.50 rotation. 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.

Author note: The 7.1 changes make some of the information below about 2.50 GNB no longer accurate, and will be updated ASAP. The basic priorities are still the same, but some of the finer details have changed.

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.

After the opener and between No Mercy windows, continue the rotation with the following filler priorities:

1. Use Gnashing Fang combo and Blasting Zone as soon as they are ready. Ensure you have a Cartridge to use Gnashing Fang immediately!
2. Use Burst Strike to avoid overcapping Cartridges.
3. 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:

1. Use Double Down, Gnashing Fang, Blasting Zone, and Bow Shock as soon as they are ready.
2. 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:

1. Burst Strike before entering No Mercy, then weave No Mercy followed by Hypervelocity to get some extra potency in the buff.
2. Use Double Down, Gnashing Fang, Blasting Zone, Bow Shock, and Bloodfest as soon as they are ready. Bloodfest should be used after Double Down.
3. Use Sonic Break after Double Down. This will mirror where it was used in the opener.
4. Finish the Gnashing Fang combo, then use the entire Lion Heart combo inside of No Mercy's buff.

Some of the core principles behind 2.50 GNB, such as the concept of the 0/2 loop, changed pretty significantly with the change from Double Down costing two cartridges, to only costing one. Therefore, this section has been removed for the time being and will be updated soon with up-to-date 7.1 information. The above priorities for 2.50 GNB are updated for 7.1.

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