Azur Lane(EN) In-Depth Equipment Guide Series: Battleship/Battlecruiser/Monitor Main Guns

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Battleship/Battlecruiser/Monitor Main Gun Overview

Battleship(BB)/Battlecruiser(BC)/Monitor(BM) main guns are quite different from the other guns.
1. The firing arc allows them to go past shields as torpedoes do.
2. HE shells are very much preferred in PvE. Not only because HE is effectitve against most enemies you see, but more because AP has very punishing modifiers against light armored ships. To see all ammo modifiers, click here.
3. DPS, although still useful, is a much less important factor when evaluating the strength of a BB gun. This has to do with how infrequently BBs, BCs and BMs fire. Therefore, calculating timeframe and damage per salvo is far more relevant.

One thing to note is that HE shells from BB guns are the primary source of fire damage.
Take a look at the fire damage equation:

Fire damage = (1+Firepower/100)*(Weapon damage)*(Weapon modifier)*(Weapon efficiency)*(fire damage coefficient)+5

Fire chance(ignition): DD guns = 1%, CL guns = 3%, CA guns = 8%, BB guns = 50%, Sanshiki(Type 3) = 30%

Fire damage coefficient is 0.6 for standard HE shells and 1.2 for Sanshiki(Type 3) shells. To see the definition of the other variables in the equation, click here.

You can see that fire damage and chance are maximized with high caliber guns and high firepower stat. This is why ships that use BB guns are the major contributors to fire damage.

Battleship/Battlecruiser/Monitor Main Gun Analyses

Triple 406mm MK6 Main Gun

Damage	156x3	Stats	FP+25
Base Fire Rate	24.02s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	22°	Ammo	HE

The infamous "MK6", a purple gun that made most gold guns look like shit.

This has almost everything you want in a BB gun. High damage per salvo, high DPS, low spread, reasonable reload, HE shells.

Not really that hard to obtain. In most cases this is the best gun for your BB/BC/BM(I'm going to just say BB from now on since I'm tired, they all use the same guns).

Obtainable from: US boxes, 6-2, 6-3


410mm Mounted Gun

Damage	154x2	Stats	FP+25
Base Fire Rate	20.02s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	20°	Ammo	HE

Another great BB gun. Generally considered less powerful than MK6(but with very important exceptions).

Reload is significantly faster. Damage per shot is actually less, despite of having only 2 shells vs 3 and at higher caliber.

Accuracy is noticeably better due to tighter spread. It's unlikely that you'll miss a shot if you aim well. However, this can be unsuitable for maps full of fast-moving enemies. On those maps MK6's worse accuracy becomes an advantage because its salvo covers more area.

Currently has the highest potential for fire damage in the game. This has to do with the fact that this gun has inherent weapon modifier of 110%, while MK6 has 105%. Weapon modifier is part of the fire damage equation, and both guns are pretty much equal in all other variables. For explanations of weapon modifiers, click here, then scroll down to see the table that lists these modifiers.

It's often used on ships that need to trigger their firing-based skills(Hood etc) because the shorter reload can help bringing out those skills more than MK6 does.

This gun has the potential to replace MK6 as the top pick for BB guns in the future. This is a good time to discuss the comparison.

The reason that MK6 is always used in most cases(especially in early mid game) is that it has very high per salvo damage(not the same thing as DPS, like I said earlier DPS is not very useful in assessing BB guns). Three giant fireballs will clear a big portion of your screen.

The 410mm on the other hand feels very half-assed even if both shots land. If they don't die from it it's very frustrating and lengthens your battle for a whole new round of reload, making your grind longer.

However, these cases are assuming low to moderate firepower stats.

At some point, EN will have level uncapping and you will have Lv 120+ BBs. When the base firepower rises, 410mm's faster reload will become much more advantageous. The per salvo damage will be adequate to clear your enemies (especially preboss battles) and you won't really leave them half-dead. Coupled with BB auxillaries (special shells that increase crits), this makes you clear maps faster than using MK6.

On top of all that you can still enjoy the higher fire damage, faster reload for skill triggers etc.

This won't happen any time soon for EN so you should still treasure your MK6s. Just know that future trend might favor 410mm. A final caveat would be that the MK6 won't become a "bad" gun by any means, even in the future, because Azur Lane is an easy game. Both guns have their own sets of characteristics that make them suitable for some things but not for others. It's just that for early to mid game, MK6's advantages are more apparent. In end game(with the addition of new game features/contents), 410mm's advantages become more apparent.

Obtainable from: JP boxes, 6-3, 7-3, 12-4

Twin 381mm Main Gun

Damage	128x2	Stats	FP+25
Base Fire Rate	18.72s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	20°	Ammo	AP

The "Hood gun". Very fast reload. Suited for triggering firing-based skills(like Hood's).

Shell type is AP. Not good for PvE. Base damage per salvo is also not too great.

It's often considered the rate of fire specialization gun. You gain a faster reload at the cost of actual gun damage. It's fine for ships with already low firepower(like Hood) whose shelling damage is something you plan to give up anyway, for the purpose of triggering skills more.

Whether this is worth it is still situational dependent, though.  This is where timeframe control in BB guns need to be considered.

You can compare this to the 410mm above. Is the reload-damage tradeoff really worth it? If you know the battles are going to be short (usually non-boss) and you wont get to trigger your skill more than once no matter how much you cut the reload, then go ahead and use the 410mm. It's not like you can squeeze another round of firing into that battle anyway, might as well go for more damage.

If you're in a situation where the battle is long, and you want consistent gun firing skill triggers(like a boss battle of some kind), then it's fine to use this on a low-firepower gun to min-max. If you know you will get to fire your BB main gun many times, then this is a worthwhile tradeoff.

This is just one example. In general, for guns with stat tradeoffs, it's best to consider what are you expecting to encounter/to achieve in specific maps.

Obtainable from: UK boxes, 6-2

Twin 381mm Advanced Main Gun

Damage	133x2	Stats	FP+45
Base Fire Rate	17.96s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	22°	Ammo	HE

The "true" Hood gun. An improved version of the gun above, fixing most of the issues it had. Better stats all around. The most important fix is the AP->HE shell change. This allows it to be extremely versatile.
Often considered the best BB main gun for BBs with firing-based skill triggers because it has useful ROF advantage without losing much of stats if at all. Because this is commonly considered strictly better to many normal BB guns, acquisition of it is limited. As of now this equipment is core data exchange/event only.

Obtainable from: Core data, Research

Prototype Triple 381mm Gun

Damage	142x3	Stats	FP+45
Base Fire Rate	23.15s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	22°	Ammo	HE

Very close to the MK6. Despite of this being a research weapon, it doesn't bring many new things to the table.
FP+45 is better than the MK6, but base damage is lower, and on high level ships the extra firepower is not enough to make up for the lower base damage. Rate of fire is faster than the MK6, albeit minimally.
Currently situated awkwardly between high damage BB guns and fast reload BB guns, while leaning very heavily on the high damage end of the spectrum. It pretty much functions the same as the MK with minor ROF bonus. Often considered as the lowest priority among research equipments.

Obtainable from: Research

Prototype Triple 410mm Gun

Damage	154x3	Stats	FP+45
Base Fire Rate	24.14s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	22°	Ammo	AP

The best AP option in the game as of now. Often seen as the AP version of the MK6 as their stats are almost identical except for ammo type.

With the introduction of the new AP penetration mechanic and later map mid-armor enemies, this AP guns will likely see more play. It is good to keep this option available.

Obtainable from: Research

Twin 406mm MK5 Main Gun

Damage	154x2	Stats	FP+25
Base Fire Rate	21.15s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	20°	Ammo	AP

The MK5 is far less popular than the MK6. The AP shell type sealed its fate as a PvP weapon.

As mentioned before, AP guns have very punishing modifiers in most PvE battles. The damage this gun does in those battles is highly inadequate.

Otherwise the stats are not too bad. It's probably the best normally obtainable AP gun. If you have special need for AP gun(for example PvP or in a battle where you know the boss has medium armor) then go ahead and use this gun.

Obtainable from: US boxes, 6-1, 6-3

Triple 406mm Main Gun

Damage	154x3	Stats	FP+45
Base Fire Rate	24.02s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	22°	Ammo	Normal

Generally considered a terrible choice.

Stats are almost identical to MK6(2 less damage per shot). Theoretical DPS is comparable as well. But it fires normal shells, rendering this gun pretty much useless.

It is probably better known as the Barracuda cockblocker, because when you open a UK box you'll probably get this guy instead of something useful like a gold Barracuda.

The one relevant stat is the firepower boost. Because this is a gold gun, it's +45 instead of +25. In ships with shell type-modifying skills that changes the shell type of this gun to something other than normal, this gun can become useful. The reason is that this gun's base stats aren't all that bad(comparable to MK6), and the +45 FP can boost your final gun damage. Its only drawback is the shell type. So if you managed to take care of that, then this becomes usable.

The gun is still very disappointing for almost all situations though. You can scrap if you want.

Obtainable from: UK boxes, 6-3

Quadruple 356mm Main Gun

Damage	108x4	Stats	FP+45
Base Fire Rate	29.19s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	25°	Ammo	HE

Another classic case to study BB gun timeframe control.

On paper this gun is very disappointing, and in a lot of times, in practice as well.

Every salvo has 4 shells. As expected, each does less damage than the shells from twin and triple guns. It also has a very slow reload to compensate. The shell spread is also very wide, as expected from a quad gun. Shell is HE, which is good regardless of the rest.

As a result, the theoretical DPS of this gun is very bad. The gun is inaccurate, and takes forever to reload.

However, the per salvo burst damage is still reasonable. Total number doesn't add up to MK6's assuming all shells hit, but it does cover a wider area and hit more stuff. Not to mention the gold gun firepower buff is at 45 which might matter for some cases(skills with firepower scaling).
One example is to use this gun to buff the barrage damage of monitors with time-triggered barrages(Terror and Erebus). Because they have low firepower, the +45 can help with the barrage's firepower scaling.

For shorter battles with many enemies where you won't get to your second round of shelling anyway, this gun is usable for its AOE to clear things faster. To reiterate, when comparing this to another gun, if the battle doesn't last long enough for the other gun to fire twice, then the other gun's DPS is irrelevant, and only salvo damage matters. And if this gun wins in salvo damage than the other gun, then this gun is judged more favorably.

Long reload of BB guns complicates a lot of things. Coupled with other attributes of BB guns, things might not always be apparent.

But even with all things considered, this gun's usage is still likely very niche. In most cases you can still brainlessly spam MK6.

Obtainable from: UK boxes

Quadruple 380mm Main Gun (Mle 1935)

Damage	120x4	Stats	FP+45
Base Fire Rate	25.80s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	24°	Ammo	HE

The "Jean Bart" gun that probably only should be used on Jean Bart.
Slow reload for mediocre damage. The firing pattern is what is known as "pseudo-quad" compared to the other quad gun (356mm). Instead of firing 4 shells it fires 2x2. The firing animation's time slowdown only applies to the first 2 and not the second 2. The accuracy suffers a bit as a result. Although this functionally fires like a twin gun, the dispersion is horrendous compared to the true twin guns like 381mm or the 410mm, further exacerbating the accuracy problem.

But based on the way Jean Bart is built(main gun preload) and her skills that check for this gun, this gun becomes the best option for her in most situations. It's not recommended to use this on other ships. You likely won't need more than one of this at this time.

Obtainable from: Events

Twin 380mm Main Gun (SK C)

Damage	132x2	Stats	FP+45
Base Fire Rate	18.39s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	20°	Ammo	AP

Very accurate AP gun. But it's an AP gun.
Reload is very fast. Overall it's very similar to the purple Twin 381mm, except it's better in every way.
Fast reloading guns have a usage in triggering firing-dependent BB skills, but the AP ammo has limited usage.
Some may opt to use this for the skill purpose, but eventually the introduction of 381mm kai solves the dilemma by offering similarly good reload and HE ammo, making this gun somewhat obsolete.

Obtainable from: DE boxes

Triple 283mm Main Gun (SK C/34)

Damage	88x3	Stats	FP+25
Base Fire Rate	16.63s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	22°	Ammo	Normal

The BB main gun with the fastest reload in the game.
Can be used to maximize skill triggers. The huge downside is that the ammo type is normal (as a result of a previous CN nerf). Therefore this gun isn't nearly as sought after as one might expect.
For skill trigger purposes, the introduction of 381mm kai makes this somewhat obsolete, as it offers a a near-perfect combination of damage potential and reload.

However, being ranked #1 in a stat is still an achievement. Future skill interactions may make this worthwhile under very niche conditions. If you have inventory space I'd keep one even if you are not using it.

Note that this gun has the exact same equipment image as the CA version of this gun. For more details see the CA main gun page.

Obtainable from: DE boxes

356mm Mounted Gun

Damage	88x2	Stats	FP+12
Base Fire Rate	19.27s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	20°	Ammo	HE

Although this is a blue gun, it has very fast reload. Not as fast as the purple 381mm, but still very good.

HE shell makes this relevant in most PvE situations.

For ships like Hood that have good firing-dependent triggers, this is a great choice as a transitional gun before you get the purple 410mm or the purple 381mm purple. It has a good balance between shelling damage and skill trigger while having useful HE shells.

Obtainable from: JP boxes, 1-4

Triple 356mm Main Gun

Damage	84x3	Stats	FP+12
Base Fire Rate	27.17s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	22°	Ammo	HE

Good HE shells and decent damage for a blue gun.

DPS is lower than the blue 356mm above. Mostly due to the reload being a bit too slow.

Then again, salvo damage is higher than the blue 356mm above. So you should calculate your battle timeframes in order to decide which one to use. But then this is just a transitional gun so it's probably not worth it to think too hard. Eventually you'll move on to better stuff.

Obtainable from: US boxes, 2-1


410mm Mounted Gun (3rd Year Type)

Damage	20x10x2	Stats	FP+25, AA+25
Base Fire Rate	19.29s/wave	Attribute	Volley
Range	200	Firing Angle	50°
Spread Range	20°	Ammo	Sanshiki

Modified version of the purple 410mm Mounted Gun.

As of now this gun is rather useless.

Theoretical DPS is the highest in game among BB guns, but it comes with some serious baggage.

The two big shells split into smaller shells in mid sky and tiny fragments spray over the enemy side of the screen, each doing a tiny amount of damage. Theoretical DPS is calculated with the assumption that ALL the fragments hit, which is utterly impossible in practice.

The shell type is sanshiki(3rd year type) shells and not HE. It's a kind of incendiary weapon. As discussed in the overview, sanshiki has a burn damage coefficient of 1.2 and not the normal 0.6 that HE shells have. But the chance of ignition is 20% lower for some reason. Firing BB guns purely for the purpose of ignition and fire damage is a bad tactic to begin with, but even if you wanted these small fragments to light enemies up they probably won't do a great job anyway.

Because this is an event reward, you should think twice before you redeem this gun because of its limited usage. One scenario I can think of that this gun might actually utilize all of its theoretical DPS would be one in which the player attacks a gigantic, immobile enemy that fills up the whole right side of the screen(for example, some enemy that represents a port or other land structures of some kind). That way all the fragments will hit and set the buildings on fire, giving you full damage numbers and fire bonus.

But as of now, this kind of enemies didn't appear on CN/JP yet so be cautious about whether you want to spend for this gun.

Obtainable from: Events, Research