FEATURES of LRMs to keep in mind (some of these might be bugs):
---hitting CT: Missiles hitting CT on a mech do more damage, also they aim for this so you will get many hit here.
---Targeted Mech Size: Larger mechs take more damage per hit from LRMs (this might only be caused by more CT hits, hard to tell)
---Targeted Mech Speed: With direct fired missiles (no Spotter) you will be able to hit almost all mechs moving under 90 kph just fine, and Mechs Blackjack or smaller moving 40-60 kph. With the spotted firing arc, or really long range direct fire, the firing arc will end more vertically this reduces your odds of hitting a moving mech.
Assaults you should still be fine against always, large mechs moving over 60 kph you will start missing alot and at 100 kph you will rarely hit at all. Small mechs moving at all you will miss alot, and ones moving over 80 kph you will likely never hit.
USING LRMs:
Artemis (1 ton/ 1 Slot on every missile launcher): This will speed up the time it takes for you to aquire a target, allow your missiles to track for longer after you lose LoS, and decreases missile Spread. The decrease in spread makes an ALRM20 spread about the same as an LRM10, or an ALRM10 about the same as an LRM5. I would recommend not using this for LRM5 and LRM10, but in general use it for LRM15, and LRM20. In the description it says this gives an increase to missile tracking strength, this appears to translate in game to the decreased spread and/or the increase in target retention duration, I am not yet 100% certain on this and will update once I find out for sure.
Volley Size and Spread: Volley size is affected by both number and size of launchers, and number of tubes on a hardpoint. If a hardpoint has say 10 tubes and you put an LRM20 launcher in it it will fire 2x10 missile volleys about 0.5 seconds apart. Missile Spread is per launcher, so 2x LRM5 will have the same spread as 1xLRM5. A LRM 10 in a 5 tube hardpoint would also have the same spread as an LRM5. This makes it preferable to have multiple smaller launchers over one larger launcher (though this might cost heat and tonnage). The other thing to factor in is does the enemy have AMS since it shoots down about the same number of missiles per volley whether you fire 10 or 40 at them. Essentially assume for each enemy AMS you are losing 8 missiles, so firing 1 LRM 20 would only have 12 missiles reach them, firing 2 LRM 20 would have 32 missiles reach them (assuming single AMS).
Having a smaller spread will both get more hits, and the hits you get will be to CT more often. The exception is against small fast moving targets where a small spread will often completely miss, a large spread will often still get 1-4 hits. The few hits you gain from a large spread are really not worth it though smaller is always better to have.
TAG (1 ton/ 1 Energy slot): This both tightens spread, and allows you to target an enemy that is protected by ECM. Since you have to hold this on target constantly it is only very good against slow moving or large targets, but can make a huge difference against Assaults with ECM protection, so unless you need all your energy slots for other things this is most likely worth taking. The description on this says it increases tracking strength, in my experience this is transfered in game as a tightened spread, and possibly a longer lock time I am not yet certain on this as you seldom lose lock unless the target is moving quickly, by which time you will probably no longer have the TAG on them anyway.
NARC: (3 tons/ 2 slots, 12 ammo per ton): this puts a beacon that lasts 30 seconds on an enemy mech, while it is on your missiles will fire at it with a smaller spread, and you hold target better. It does NOT penetrate ECM, it has very short range, and is in general BAD. Do not use this unless you are a dedicated spotter for a group that knows how to make use of it. And even then its still not worth it. Also it does not stack with Artemis for spread reduction.
BAP {beagle active probe} (1.5 tons/ 2 slots) and ECM {Electronic countermeasures} (1.5 tons / 2 slots): You cannot fire at mechs within 180m of a enemy with ECM, Unless you or a friendly mech uses TAG, or a friendly Mech gets close enough and has BAP. You cannot fire if an enemy mech with ECM is under 180m from you unless you have BAP. BAP also raises targeting range, and decreases time to gain details on enemy targetted mechs.
Modules:
Targeting Decay: (Very useful) will let you maintain target for 2.75/3.5 seconds (2 without) after you lose line of sight on a target. Not certain if this also affects spotted targets, either way it is very good.
Sensor Range: probably not worth it, missiles are easy to dodge at over 750m anyway and if using BAP you can target to near 900m so while this won't hurt for lining up potential targets it is of minimal value.
no other modules right now really affect LRMs, though many like seismic(OP) are great for all mechs.
Piloting:
The key points here are Range, Cover, and where your team is.
---Range: stay over 300m and under 750m from targets. If you get too close they will dart inside your range before you can get your punches in. If you are too far they will have too much time to evade.
---MY team: you want to be about 100-200m behind your main pack, stay close in case enemies come to you, but you want to be a bit back so you can still fire at any brawlers trying to engage. (being right in your pack is not bad, but being massively seperated is asking for lights to come kill you)
---Cover: Learn the maps, you want to be in an area where you have good cover options, but most enemies coming near do not. (an example in River city, sitting near the upper base you have great line of sight to every direction, but only a few routes to you have much cover) (A example of where not to be: Middle of plateau in Alpine summit, you have no cover anyone could snipe from behind cover to most directions. In canyon map: in a canyon {unless sneaking somewhere} the sides are high enough you can't fire over them easily, and enemies can get under 200m before you can target them {possible exception to this if using JJ, then you can jump in and out of cover})
Mech Chassis: (max missiles, within reason)
---True Boats:
* Hunchback 4J (ALRM 40, LRM 40) not my favorite, but it is smaller and can still fire a full 40 missile volley
* Catapult A1/C1/C4 (ALRM 70, LRM 90) don't try to hit max on these though better to run a 3-4x(A)LRM15 for 45-60 missile volleys and have more room to put in a larger engine, JJ, Ammo, and backup weapons
* Jaggermech JM6A (ALRM 60/ LRM 60) 4x 15 tube hardpoints works similarly to the Awesome, a little lighter but similar in play and effectiveness
* Awesome 8R (ALRM 60/ LRM 60) has 4x 15 tube hardpoints so can get a nice 60 LRM launch, not worth trying to fit in LRM 20s
* Stalker 3H/5M/5S (ALRM 80, LRM 80/ ALRM 85, LRM 90) due to weight over ALRM 70, LRM 80 is highle impractical 3H is betterfor a large single volley (2xALRM20, 2xALRM5), 5M is better at repeated small volleys probably preferable going (5xALRM15, or 2xLRM20, 3xLRM15). 5S is only optional as it has 2 AMS if you run into a high missile boat Meta.
* Highlander 733 (ALRM 70, LRM 75) good tubes, JJ capable, not many energy slots for backup weapons still an excellent choice
* Atlas DDC (ALRM45, ALRM 35+ECM, LRM 45+ECM) small tube number is bad vs AMS do not recommend boating this, it does have the ECM though and if you have the chassis and wish to try it its not bad, just not as good as an ATLAS DDC should be.
---Dedicated LRM skirmishers: (fast keep at range and pepper enemies with smaller volleys) {not noting Artemis}
* Raven 3L (LRM15 + LRM5) or (LRM15+ 3ML) don't do this Ravens can be so much better in other roles
* Centurion (3xLRM10 or 2xLRM10 + Energy) you can fit 3xLRM 10 with a standard engine but only barely, better to go a really fast LRM 20 with some energy weapons using a standard engine using the CN9-AL. If you go the CN9-A route for the extra launcher go with the XL engine even though you lose zombiehood, and use the tons for some LL or such. Without zombie though use another chassis unless you really love these.
* Trebuchet 7M/3C/5N (2xLRM15) 7M for JJ, 3C for bigger engine, this is one of the better chassis to run a mech like this with, Apparently the 5N has better torso twist allowing you to fire while running away better.
* Catapult C1 (2xLRM15) has JJ, and can move a resonable speed, carry lots of energy for lights hunting you
---Other types of builds for examples
* Stalker 5M (4LL, 5xLRM5) can launch 25 missile volleys at higher rate of fire and has alot of punch with its energy weapons {also you can get a nice steady stream firing them seperately if enemy has no AMS}
* Highlander 733 (Gauss + 2ERPPC, 4x LRM5) 20 missile volleys at good rate of fire, and can snipe
AMMO: 2 theories here; one is the bring enough to fire at everything and suppress the enemy, in this case bring at least 1 ton of ammo for every 5 LRMs in a volley (18 launches of all missiles). The second is to make your shots count and take only 1 ton for every 10 LRMs (9 launches of all missiles). If you only take this many you should have strong backup weapons at least 4 ML, or 2LL or more. (remember you can setup a separate firing group to chain fire or such, allowing you to fire a single launcher at worse targets to make the run for cover without wasting as much ammo)
When to Fire: (assuming they do not have perfect cover)
---200-400m and have a lock at all, FIRE they will reach the target before it can break lock even if you lose LoS.
---400-700m; If you have target yourself, and the enemy is at least 1 second from cover FIRE sometimes they might break lock in time, but normally missiles will hit. If your target is being spotted for you, still fire, unless you know the enemy will reach cover since your missiles will often reach them in time.
---700m-900m; Only fire if they are on a wide open plain, or you have a spotter you know will hold target.
---900-1000m; only fire if they have no cover and are moving toward you at speed, even then do not expect to hit much, this is only worth it if you have ammo to spare.
---Target has NARC on it: go for it, any player that uses NARC should know how to spot for you still over 700m expect under 60% hit rate
---In pugs do not expect tag from others to mean much, and expect other players to switch targets while your missiles are midair. If you are on voicechat this problem can probably be removed with communication.
---If there is an ECM bubble, try to tag an assault not near cover to fire at, smaller targets will normally break your tag too easily (Jaggermech is another good target, DDC first though if you can)
---If you see AMS firing at your missiles depending on your volley size either ignore it or find a new target (refer to AMS section)
---If you have a low quality target you still might want to fire one launchers missiles at it. This will give it a missiles incoming warning and make it run for cover(read stop firing at your friends).
---If the enemy is a Blackjack or smaller and not standing still, try to find another target, feel free to fire 1 launcher at them to make them keep running, but you will likely do no significant damage to this size of target.
Spotting for a missile Boat:
---All mechs: (there is a missiles incoming icon on top of target box on your hud if you see it, might want to hold that target for a few seconds if it does not inconvenience you too much.) Use R to target an enemy near you if you plan to be facing that target for over 5 seconds. Assume at least 2 seconds before missiles are fired, and 5 seconds of flight time. That with the extra 2 seconds after target is lost will allow the missiles to hit. If you are popping over a hill to snipe something don't bother grabbing a target as you will lose it instantly. (For groups that know what they are doing popping over and grabbing a target, then losing it, and popping over to get the same target again can be effective as the missile boat can reaquire target while missiles are in air for a good hit. This is not very workable in pugs)
---Dedicated spotters: Aside from holding the target till missiles hit (sometimes multiple volleys), Keep an eye on where your missile boats are, remember they have an effective range of only about 800m so if you are targeting something 950m+ away it doesn't help them much. Using Tag definitely go for DDC first if you can. Aside from that any Assaults are best. If you run ECM turning it to counter and running around near an enemy ECM can be very effective (if you survive). If you have enough missiles aiming at a target that doesn't know where you are, it might be better to stay hidden than chip in with a single LL or such. As a fast Missile skirmisher with a TAG or such if you have other Missile boats in group even a PUG try and touch base near beginning, if they are adding their 60 missiles to your 30 things will die alot faster.
---UAV (module): This can be used effectively by a fast scout, remember it has limited range so you need to launch it while near the enemy targets. And it has limited duration, 45-60 seconds, so make sure your LRM boats are in range (<900m) before using it, or it might be wasted. This can be used to either maintain line of sight, or counter ECM. If they have a group with DDCs you probably want to save it for near that group.
AVOIDING LRMs
Using Cover:
Ok first there are 3 types of cover you can use.
---Vertical Cover: sitting under a bridge or platform (river city near theta is a good example), also under some upthrusts in Tourmaline Desert. Spotted missiles with a high arc will hit the cover above you from any angle while you keep line of sight to fire at other targets. Non spotted missiles have a shallower arc, though even then if you position yourself right the missiles will hit it not you.
---Tall buildings and cliffs: If you are near these they will stop all missiles they should be at least 2-3 times the height of your mech. If you are further back from them they should be at least 6-8 times the height of your mech.
---Low hills and buildings, anything with a shallow angle: These only stop line of sight helping you break a lock, they will not stop the missiles themselves. Remember the enemy mech will hold lock for 2-3.5 seconds after you break LoS, so either keep moving behind cover, or stop then move again shortly before missiles hit.
Moving: Any movement will reduce the number of missiles hitting you. Moving directly away from the missiles is worst, directly towards them is nearly as bad. You want to be moving direction perpendicular to the flight path to avoid the most damage (pretty much the same as against every other weapon). If you can move at over 100 kph, and move perpendicular to the flight path, almost no missiles will ever hit you. At over 130 kph missile hits are so rare you can almost totally ignore LRMs.
AMS (Range 90/ MAX 200): AMS fires at missiles going toward you or any friendly mechs near to you. Note it will do decreased damage the further away it is from the missiles so you really need to stay within 120m of friends for AMS to shield each other well. If missiles are fired over you at another mech they will be in range for longer and have 1.5-2 times as many shot down, if they are fired at a mech to the side or front of you, AMS will shoot down far less. Each AMS will shoot down about 7-9 missiles aimed at you.
# of AMS to be effective, VS 20 missile or smaller volley 1 AMS will help alot, vs 20-40 missiles you really need 2+ AMS, vs 40-60 LRM volley (missile boat) 3-4 AMS will reduce damage to very low levels if you are near each other.
ECM: ECM can be used by either standing near the enemy if they do not have BAP and totally preventing them from firing, or staying near your group and preventing the group from being fired upon. If your group has good cover, or the enemy boat is with a group, staying near yours will be safer and very effective (need cover to prevent TAG). If you find an enemy missile boat on its own they tend to be easy prey for a light, and you prevent them from firing while you kill them so this can be very effective.
---IF you are a Atlas DDC, ECM does not prevent them from using tag, you are not immune to missiles, you have a very good defence, but do not just stand in one spot facing a missile boat pumping rounds into you, it will hurt bad.
Torso Twist: Torso twisting can help a ton on some chassis (Awesome, Stalker, Catapult, Hunchback, etc...), on others it is not so useful (Atlas, Jaggermech).
---Against direct fire missiles with the lower firing arc (especially at close range) torso twisting will act almost exactly the same as against direct fire weapons.
---Against spotted missiles or at very long range, the missiles end there flight at a very steep angle of descent. This means they will be aiming for the top of your mech and will usually hit front torso even if you are facing away from them. Remember too that the missiles are changing path to come toward you if you are moving(you should be), so if you are moving sidewards, they will actually hit your mech from the side you are walking away from them on. If you are moving toward them they will hit more directly from above. If you are walking away from them, their angle will become more shallow allowing more mechs to shield with arms if needed. Usually though the best form of movement is perpendicular to the flight path of the missiles, with your torso facing the enemy missile boat, this will send more of the damage to your arms, while allowing you to freely return fire. (Some mechs such as the hunchback may wish to keep their hunch on the side of their mech away from the direction the missiles are approaching from as it is a very big target for them to hit.)
Edit Log: Modified capitalization in Title
Added Trebuchet 5N as skirmisher, clarified Artemis/TAG: thanks 80bit
Added UAVs, thanks Darwins Dog
Edited by Ningyo, 15 June 2013 - 04:05 PM.