Thread in 'Mech Build and System Tests' started by skribs, Jan 18, 2015.

  1. skribs

    skribs Min-Max Maniac


    I am curious about the best combination of LRMs for general use, and the best combination of other bonuses. Is a lot of little ones good? How about a couple big ones? Should I mix and match, or go all out? What about going with a launcher that has more tubes than the hardpoint? How does chainfire work with those launchers? What about various addons like TAG, NARC, and Artemis, and how they work together?


    I am going into this with the philosophy that you should always have TAG and BAP to counter ECM, and enough ammunition to last the match (as well as short range firepower for those situations). I am also under the impression that 3-4x LRM10 or 4-6x LRM5 without Artemis makes a good DPS/Support mech, but running a stacked 2xALRM15 or 2xALRM20 build will give more consistent results on the battlefield.


    Specifically, I will be running tests to isolate various factors and see how the spread varies. To test this, I will run different Mechs with different combinations of LRMs and addons, and I will test the combinations using 180 rounds of LRM ammunition. I will then screen capture the ragdoll, and/or record how many shots it took to bring it down. I will be testing on the same map, against the same mech, at the same range and angle, so there will be very little variance.

    The map will be Frozen City Night, the target will be the Atlas, and the range will be 400m (+/- 2m). This range is between the minimum for LRMs and maximum for NARC.

    I will only do 1 test per variable. This is because I will be doing over 20 tests already, and I will use the fact that I am using anywhere from 6 to 36 shots (LRM30 combinations to LRM5 standalone) as the sample size. I will run the following tests:

    1. LRM size (LRM5, LRM10, LRM15, and LRM20, in the STK-3H)

    2. LRM boat quantity (LRM5 through 5xLRM5 in alpha, and then 5xLRM in chain fire, in the STK-5M)

    3. LRM variable stacking (2xLRM15, LRM20+LRM10, LRM15+LRM10+LRM5, LRM20+2x5, LRM15+3x5 in the STK-3H)

    4. LRM tube test (LRM20 in AWS-9M arm with 2 tubes)

    5. TAG, NARC, and ARTEMIS individual tests with STK-3H and LRM20

    6. TAG+NARC, NARC+ARTEMIS, TAG+ARTEMIS, and TAG+NARC+ARTEMIS combo tests with STK-3H and LRM20

    7. Range test (LRM20 at 200m, 400m, and 600m in STK-3H)

    8. Clan LRM Test (CLRM20 in the Timberwolf)

    I will also do a test in a Mech with varying tubes to see how they work with chain fire vs. alpha fire, for posterity, using VTR-DS with 2xLRM10. I will be doing this to see if the Mech does 10 on each shot when chain firing, or if it does 6 with the second shot.


    I’m not going to post charts of DPS and DPH numbers. Instead, I’m going to go over generalizations that can be made about the various builds. I am going to be looking at comparisons of different combinations for a LRM30 build, and then extrapolate from there. The three combinations I’m looking at are LRM15x2, LRM10x3, and LRM20+10. I will then extrapolate further into LRM20+5+5 and LRM15+10+5 to give a better idea of the concepts.

    First, let’s look at the LRM15s. They will fire in 4.25 seconds in alpha mode. They will be of equal heat cost to LRM20+LRM10, and more efficient than 3x10 (even if the 10s didn’t have ghost heat, they would be less efficient). Overall, a very balanced setup.

    Next, the 3x10 build. It will fire in 3.75 seconds instead of 4.25, giving more burst DPS than LRM15s. If you decide to chain fire instead, then they will run cooler than alpha striking (due to ghost heat). Their DPS will still be high, but full DPS will be delayed by 1 second. This ramp-up slows them down slightly, but they’ll make up for it with sustained spam. However, where the LRM15s will weigh 14-16 tons and take up 6-8 slots, the LRM10s will weigh 15-18 tons and take up 6-9 slots (without-with ARTEMIS). The extra 1-2 tons can mean ammo, lasers, armor, engine, or DHS.

    Now, how about the 20+10 build? It can alpha in 4.75 seconds, meaning if you wait to alpha it will be slower than the LRM15s, but cost the same heat (10 heat for 30 LRMs). It will weigh 15-17 tons and take up 7-9 slots, making it better or worse than the 3x10 in terms of space as the LRM10 build. It can be chained, spammed (in which case the first shots are alpha’d and the subsequent shots are desynchronized to fire as soon as they are off cooldown), or alpha’d.

    The problem with using alpha strike in this variant is you may miss your timing and fire the 10 before the 20, which would result in less damage against AMS-shielded Mechs. With the 10s or the 15s, you can spam the alpha button and fire whenever your cooldown is up. But with the 20+10 build, you sacrifice your capability to do that if you want to do 30 damage every time.

    Now, let’s look at other builds. 20+5+5 also gives you 30, but now your alpha strikes have Ghost Heat. And guess what? The Ghost Heat will apply to the 20. You also have the same problems you had with 20+10. The same is true of 15+10+5, you will get Ghost Heat on the 15, and you will lose the ability to synchronize your alpha strikes.

    There are two other problems with mixing and matching LRMs: Quirks and Modules. If you have quirks for a specific LRM size (especially Range) it would be a good idea to focus on that quirk. Similarly, if you have a range or cooldown module equipped, you get the most out of it by using the same size LRMs.

    Overall, I think the best bet in terms of raw numbers is to get 2x15 or 2x20 to use with alpha fire, or get 3+ 10s or 4+ 5s to spam fire. Quirks help, and Assaults can handle 3x15 if they have the slots.


    Mechs were chosen due to a combination of their hardpoints and their availability in my Mechbays. Also note that as the experiment was being done, some reordering was done from the planning phase to the data collection phase. This difference is reflected in the order shown.

    One interesting thing I learned is that if none of your LRMs are assigned weapon groups, you will not lock onto targets.

    Test 1: The LRM Launcher Size Test


    This test largely proved what many people have said about launcher size and spread. The LRM5s were able to core out the Atlas and had the least misses. The LRM10s had a moderate amount of misses, but didn’t spread out far enough to hit the arms. The 15s and the 20s had a similar spread and similar health remaining, suggesting that the jump from 15 to 20 might not be that different after all.

    Test 2: LRM Boat Quantity


    This test shows that the amount of launchers you have is irrelevant to spread. While one test failed to core the Atlas, they usually cored it on the final salvo, so the fact the armor was red means 1 extra missile probably missed. Note that with 5xLRM5 in alpha mode, the last shot was a single LRM5.

    Test 3: LRM30 Stacking


    This test shows that the spread is based on each launcher. Those with a heavy focus on 20s and 15s did about how a 20 or 15 would do, but as you added in more 10s and 5s, they did better. Note that the reason the versions with 20 did so poor is because 2/3 of the spread was based on the 20, while the 15+10+5 and 15+2x5 versions did better because only half the spread was based on the 15.

    Note: I waited until the cooldown on the slowest weapon was up before I fired again, so every shot was an alpha. If I did not do this, and instead fired every weapon on cooldown, I would have had a tighter spread as LRM5s and LRM10s would have gotten more presence in the rotation.

    Test 4: Small Tube Test


    This test actually surprised me. I expected the 2 tubes to function as if you fired 10 LRM2s in chain fire and converge tighter than the LRM5s. As you can plainly see, the LRM20 had the same spread regardless of the number of tubes it was fired from. This means if your strategy is to feed higher LRMs through a smaller number of tubes to avoid the spread, your strategy will not work.

    I also tested for posterity’s sake (and because I’ve never run under-tubed before except maybe a single SSRM2 in some builds through NARC tubes), how it works if you have multiple launchers in a Mech that has a different number of tubes. I tested this in a Dragon Slayer with 2xLRM10 in a 10-tube- and 6-tube-port torso. Here is what I found:

    · The second weapon to be put in will always fire through the 6-tube port, regardless of whether it is single fired or alpha fired. Which weapon it is will be consistent between matches.

    · Your cooldown waits until the missiles are done firing, meaning if you are trying to hold down the button to continually alpha, your shots will become more and more desynchronized as time progresses.

    Overall, I do NOT recommend using a weapon that requires more tubes than your hardpoint has. It will not help your spread, but it will cause other issues related to chain-firing and will lower your DPS.

    Test 5: Range Test


    This test result was unsurprising. LRMs spread far before they reach the 180m minimum range, and then stay at a consistent spread. This means that it doesn’t matter what range you are at for LRM spread.

    However, range is still a factor. If the target is too close, they may be able to get under your 180m range before your shots hit, in which case you would be better off using your backup weapons (or using your main weapons if LRMs are only there for support). If the target is far away, they have longer to get to cover or get out of range. Remember, under 180m and over 1000m, IS LRMs do 0 damage. Clan LRMs do reduced damage under 180m, and no damage past 1000.

    Test 6: CLRM Test


    I am wrong again! I had assumed that the cLRMs would experience an accuracy boost due to coming out one at a time. While I didn’t do multiple tests (the spread accounts for a sample size of 9 shots displayed on the same paperdoll), the cLRMs actually appear to be slightly less accurate than IS LRMs! If anything, the two are equal, but you will notice a more uniform spread and a slight increase in remaining health on the cLRMs. Inner Sphere LRMs seemed to focus on the CT but spread elsewhere, whereas cLRMs tend to be more evenly dispersed.

    I do not have the time to do all of the other tests for the cLRMs or to test them compared to all of the IS tests that I have done. It is quite possible that the cLRM5 or clan ARTEMIS is better. If someone else would like to pick up that ball and run with it, I’d be glad to see your results. However, my primary focus in this study is IS LRMs, so for now I will just assume that the principles that apply to IS LRMs apply to cLRMs as well.

    Test 7: Utility Test


    This was mainly proof of concept, as I believe the information is already out there. TAG and NARC do not stack with each other, but either will stack with ARTEMIS. Any of the three by themselves will reduce the LRM20 spread to the same as a LRM10, and combining both ARTEMIS and another will bring it somewhere between LRM10 and LRM5 spread.

    Oh, and in case you’re wondering, this was my build to test (obviously without Artemis for some of the tests):

    (Continued in Post 2)
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  2. skribs

    skribs Min-Max Maniac

    Data Analysis

    One thing to keep in mind is that these spread comparisons only compare the spread for the same number of ammo. However, you should also factor in how much ammo can be sent downrange in a given time. Depending on your mech and build, this could be based mostly on hardpoints, missile tubes, space remaining, or tonnage remaining.

    As an example, look at AWS-8T*. Yes, LRM5s will have a better spread, but with only 2 missile hardpoints and 80 tons to work with, why would you go with LRM5s over LRM15s? If you look at actual damage done, the 15s did about 85% the damage of the 5s with the same amount of missiles. However, the 15s will send 3.53 missiles downrange every second, vs. 1.54 for the 5s. Even if you take the 3.53 missiles and reduce it to 85%, the damage you are getting on target per second is higher.

    On the other hand, a KTO-18* may opt for LRM5s instead of LRM15s, because it can have 5 of them, and it doesn’t really have the tonnage available to boat 15s or even 10s and still have a decent amount of speed, armor, ammo, and backup firepower.

    *I am ignoring quirks in this statement as I am just using these hardpoints as examples.

    We learned that some things matter and some things do not matter for spread, but that there are certain caveats. We learned:

    · LRM5s have the least spread, followed by 10s, but 15s and 20s seem pretty close

    · It does not matter if you chain fire, alpha fire, or how many LRMs you have, they will have similar spread

    · If you mix-and-match LRMs, then each volley within the alpha will have the spread it would have had if fired alone. The more big launchers in your mix, the worse your spread will be

    · Shooting through a smaller number of tubes offers no efficiency benefits, but will slow your DPS compared with shooting through larger tubes

    · Range does not affect spread, but may impact your chances of hitting

    · Clan LRMs are less accurate than IS LRMs

    · ARTEMIS, TAG, and NARC show a significant improvement, but TAG and NARC do not stack

    Another consideration is the size of the Mech. I was running my tests on an Atlas, but you will see a lot different results against a Cicada.


    I decided to give utility its own section, because there is a bit to discuss here. Utility is ARTEMIS, NARC, and/or TAG; items which take up tonnage and slots without providing a direct damage increase, but that make your LRMs much better.

    NARC: NARC is a tough one to talk about. NARC is useful in that it is fire-and-forget (you don’t have to keep TAG constantly on target if you have NARC instead) and that it works after the target leaves your LOS. However, NARC functions like a ballistic, making it harder to use, and it requires you to be closer to your target. In addition, NARC takes up more tons and critical slots than TAG, and that’s before you put ammo in.

    I would not recommend an LRM boat take NARC unless it has the tonnage available and can spare a missile hardpoint. If you have an energy slot available, TAG is almost always better. I would recommend NARC as a fire-and-forget weapon for scouts or maybe for a brawler, on the condition that you know LRMs are coming in. This means it’s best for group drops or tournament weekends.

    TAG: TAG is, in my opinion, a must for LRMs. Without TAG, you will be useless against targets that are protected by ECM. If you have to choose between TAG and ARTEMIS, I would almost always say TAG, because unlike ARTEMIS:

    · TAG takes 1 critical slot and ton period, instead of 1 per tube

    · TAG can break ECM, ARTEMIS cannot

    · TAG can help friendlies out, ARTEMIS cannot

    · TAG will get you CBill and XP bonuses, ARTEMIS will not

    However, ARTEMIS does not use any extra hardpoints, it does not require you to maintain 100% accuracy with your utility piece, and you don’t have a giant beam giving away your position before you’re ready to fire.

    Of course, if you have the tonnage, space, and energy slot available, take both! They stack, and they work wonders together. Combined with energy weapons, I have quickly burned many a Mech using TAG+ALRMs.

    ARTEMIS: ARTEMIS is a great tool, but it comes at a cost. A Mech using LRMs as a secondary weapon, such as an Atlas with a single LRM15 or LRM20, will probably not notice much weight difference. An LRM boat with 2 big launchers (15s or 20s) may notice a bit of a difference, but not a lot. However, that medium Mech that is boating 5xLRM5 will notice a huge difference, as that becomes 5 slots and 5 tons that could otherwise have gone to ammo, speed, or armor.

    A general rule of thumb is the bigger your launchers are, the less launchers you have, and/or the bigger your Mech is, the more valuable Artemis is. It’s hard to exactly quantify, because it depends on the chassis and build, and how much you prioritize speed and ammo over spread.

    Non-Quantifiable Considerations

    There are other considerations that are difficult to quantify. These considerations are:

    · Other factors for success

    · AMS

    · Cover

    · Incoming Missile Warning

    · Screen Shake

    · Wasted Ammo

    Other Factors For Success: There are several other things to consider in your build besides what size LRMs to get. In my opinion, the best LRM builds have BAP and TAG to counter ECM.

    One must also have enough ammo to support their match. How much ammo depends on Mech size, your rate you can expend it, and your playstyle. I have personally gone through 2560 LRMs in a LRM30 AWS-8T before, and in CW matches I’ve gone down to less than a ton left with 4500 LRMs in storage.

    You should also have enough short-range firepower to deal with whatever comes your way. Due to the amount of space you will use for launchers and ammo, I find lasers work the best here. I like my LRM builds to have around 3-5 energy hardpoints that I can use for TAG and 2-4 lasers. Any more and I start needing DHS, any less and I have no short range firepower. Most of my damage in LRM boats comes from LRMs, but most of my kills come from the lasers, so they are important.

    Armor and engine size/type are important as well, but in general you want to have a larger engine at the expense of armor. Getting in range of your weapons and staying out of sight/range of theirs is very important. If you don’t have ARTEMIS, it’s even better to stay out of sight and let someone else spot for you.

    AMS: Okay, technically you could quantify AMS, but that would only apply to the scenario that you are shooting at 1 standing Mech with AMS. What if that target is moving? What if you are shooting over a target with AMS? What if you are shooting into a group that has a Kit Fox, a Stalker 5S, and an Anansi with a few other Mechs, totaling to more AMS than you usually see in a whole team? AMS in the field is dynamic enough that it is hard to quantify its effects.

    However, the general rule of thumb is the bigger the group of LRMs, the more will get through. If they have enough AMS to eat through 9 LRMs, for example, then chain firing 5s means you will do 0 damage. If you send in 10 at a time, you’ll do 1 damage. 15 or 20 will do 6-11. But a big fwoosh from the AWS-8R will get 51 LRMs through! This is just a random example, but you see the effect a larger group can have. It can make the difference between doing 6-6-6-6 on chain fire to doing 51 group fire in that scenario.

    Obviously, if the target does not have AMS protection, then this isn’t an issue.

    Cover: Cover is an important consideration. Just like with AMS, cover is used to block LRMs. And, like AMS, cover is best beaten by having one big fwoosh. For example, if running an AWS-8V with 3xLRM10, and you chain fire, if the target gets behind cover after the first shot hits, you sent 30 LRMs downrange to do 10 damage. But if you fire all 3 at once, then in that time frame they will hit and do 30 damage before the target runs behind cover.

    Incoming Missile Warning: If your goal is to keep the missile warning up to suppress the enemy, chain firing smaller LRMs will do so better, and at the cost of less ammo.

    Screen Shake: The screen shake from constant LRM5 spam is ridiculous and can have effects beyond just the damage dealt. This is, in my opinion, one of the biggest boons a LRM5 spammer can provide.

    Wasted Ammo: As I mentioned above, the fwoosh style will waste less ammo against targets moving to cover. However, the chain fire will waste less ammo on bad angles and target drops. Overall, this goes to the spam builds.


    It is difficult to make a one-size-fits-all assessment here, as there are a lot of factors at play. How much do you care about the spread? Wider spread means less damage on a stationary target, but more likely to hit a moving target. How big is your Mech? What are the hardpoints? Is your goal to suppress the enemy or to rip them apart?

    I hope my analysis and the various factors I have discussed helps you pick what you want for an LRM boat. I know it has certainly informed me, and I will probably look back on this as I build them in the future.


    Sorry about taking 2 posts. I hope I wasn't too wordy. There was just a LOT of different factors I wanted to analyze at once. I spent like 3 hours on this dang thing tonight!
  3. tfun90

    tfun90 Advanced Member

    Good info to have publicly available. Optimizing a LRM mech is way more difficult than a direct fire or brawl mech IMO, as it's a dozen sided balance between:
    *Heat generation/dissipation
    *Ghost Heat
    *Tube Count
    *Hardpoint Count
    *Tonnage (armor/engine/endo/ferro)
    *Desired Playstyle
    *Spotting Assistance
    *Pre-Round Insight (can you change your loadout before you drop your mech based on prior knowledge)
    *Externalities (enemy AMS/ECM level, randomness like map and tactics)

    In general, I'd just say avoid LRM15s without Artemis, and LRM20s altogether. Bring TAG or else an AFK SDR will nullify your entire existence. Consider bringing your own UAV to throw up over the main engagement, then back away and make it rain. Never stare down an enemy's barrels just to hold lock. Don't be afraid to take the vanguard, especially if your armor is fresh, and your team has already gotten chewed up.
    Last edited: Jan 18, 2015
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  4. skribs

    skribs Min-Max Maniac

    In general I agree with avoiding non-A 15s, but its hard to argue with the success of my AWS-8V with 3xLRM15.
    enileph likes this.
  5. enileph

    enileph Star Lord

    LRM15s acceptable as spammer, if you have lots of ammo. Basically instead of using +A you use the slots and tons for more ammo.
    Good side is that the spread does help you get more hits in for fast movers. And for the huge atlas and what not you just need to pump in another shot or two.

    That said, I use them only on mechs with special quirk bonus on LRM15, the extra bonus does make up for it.
    Otherwise LRM5 and LRM10.
  6. skribs

    skribs Min-Max Maniac

    I only use non-arty on the 8V to fit in an XL engine.

    Actually this test suggests that 20s aren't as bad as people give them a rap for. I do like 15s better for the weight and space efficiency, though.

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