This is a guide on how to mod your weapon because I get asked a lot about what people should mod their weapons with. That being said, there is a large difference between melee and non-melee weapons and this guide is more focused towards those players who use guns. If you do have a melee weapon only 2 slots are usable in the game right now, so the extra slots are useless--pretty, but useless.
Melee weapons can only be modded by Diferro-Tetraoxid Liquid and Titan-Carbondiclorid. Laserblade mods are available in Tech Haven, there are three that can be purchased from a vendor there and an ultima-mod which you need to collect rare pieces for. If you have an electroshocker it cannot be modded in the game at this time, so more pretty but useless slots.
First off, if you have only one slot, I would say always go for an ammo mod. Why? Because it adds extra damage beyond what a weapon would do even if you cap the damage on it...more on that later, so yes, an ammo mod.
Ammo mod basics - If you aren't killing people it doesn't matter what you mod it with as long as you mod the ammo, otherwise:
- Energy Mods - High Voltage, and Advanced: This type of damage, while fine for NPCs, is the worst thing you can possibly get against other players because almost all armor, especially power armor and psi monk armor, have energy resists up the wazoo. This is a bad choice if you think you're going to get into a fight, might get into a fight, maybe might get into a fight in the far future, have kids that might get into a fight, you get the point.
- X-Ray - Uranium, Gamma, Radiation, and Alpha: Usually when a person is distributing his/her points, he or she comes to the crucial decision of whether to put more of their points into X-Ray or more into Fire. This is really a crapshoot because depending on what they think they're up against, they'll probably armor up accordingly. Therefore it's good to have one or the other but you might choose wrong, so take your best guess and go.
- Fire - Phosphor, Flazer, Napalm, Cerosine, X-Heated, and Cooled: See the above X-Ray commentary.
- Piercing and Force - Explosive, Anti-person, Nova: Not so good against tanks and other classes, this group of ammo mods does one thing--kills psis. Because psis have a low strength and their implants lower their resistance to force, these types of damage are really a powerful psi's nightmare.
- Poison - Self explanatory stuff and War Gas: Underused, it does pretty decent damage for the level of weapons you can use it with against people because really, no one expects it. The only problem is finding a good weapon that can deal it, hence why no one expects it.
These are your weapon stats. They basically represent how much the weapon is helping you and the quality of the weapon (as in cool, outstanding, artifact). If a weapon is at 120% damage, putting a barrel on it will not raise your damage percentage. Some weapons don't need mods, period. If you have a weapon at 120% for all of these stats circled, modding it won't really do anything for you beyond the ammo mod (Hence where I said earlier about the ammo mod giving you a damage bonus above the weapon percentage) except improve the aesthetics, as in a laserpointer or a silencer. Keep this in mind when modding! The meat of the matter is this: Only mod up to 120%, otherwise what you've just stuffed into your precious slot is useless.
A quick rundown:
- Barrels: Increase your range and your damage percentage (shown below).
- Gyros: Incrase your handling which means less recoil when you fire.
- Bullet Chambers: Increase your frequency, ie, how fast you shoot.
- Adapter for Large Clips: This doesn't fit on anything right now, it's a useless dream so don't waste your money.
- Laserpointer: Aside from looking cool it causes your reticle to close faster, thus giving you faster aiming.
- Silencer: While I've heard rumors that this helps with handling, mostly what it does is keep people from being able to locate you based on where they think your sound is coming from. It's mostly nice for snipers.
- Scope: Increases your range and gives you a zoome effect that magnifies the center part of your screen, stretching it out.
Here's the real deal, take a look at those stats that are circled below.
The damage, aiming, shot frequency, and range all max out differently depending on what weapon you're using. Of course, modding your weapon with something that improves damage when you're already getting the maximum damage percentage, 178% for guns, 648% for APU Modules, or 576% for PPU Modules, isn't going to do anything for you but it will look pretty and give your weapon an impressively long name.
So how do you tell if you've maxxed a stat out with your uber-skills and therefore don't need a mod in? This is my suggestion: Get all geared up into your normal combat conditions. If you're normally going to have a certain suite of implants in when you're fighting, put those in, but don't get any psi buffs on you yet. Do a 'Show Info' on your weapon and make a note of what your percentages are. Now, get a friendly passive psi to give you a combat boost in whatever genre of weapons you've chosen, an example being a pistol combat boost 3. Do another 'Show Info' and see if anything has changed. If the stats on anything have changed, those are the things you need to mod for--if a stat hasn't changed don't put a mod that ups that particular stat in. After that uberboost wears off, put whatever psi boosts you're going to cast on yourself before you fight on, and then take a look at what your percentages are. If they're at the max, you're all good, you might need to tweak a little bit here and there because you won't always have a passive psi around.
For limited amounts of slots, what it really boils down to is your own preference: Would you rather do more damage or shoot faster? Or would you rather not do as much damage but instead have a red beam of light freaking people out when you point it at them? It's up to you now, I hope I wasn't too confusing.
Note: You can only put one mod of each specific type into a single weapon--you can put a phosphor ammo mod and a uranium ammo mod on, but not 2 phosphor ammo mods. You can put a riflebarrel and a riflegyro on, but not two riflebarrels. If a weapon is high-tech you can mode it with both an energy mod and a low tech mod. So while you can't put 2 riflebarrels onto an Enhanced Plasma Rifle, you can put a riflebarrel and an energy barrel on.
Also of note: Unless you've completely maxxed the stats on your weapon, don't bother putting more than one ammo mod in since you can really only use one type of ammo at a time and that slot would be better used for helping you max out on one of the percentages.