No brainer. Damage refers to the damage per single shot/hit of your weapon. A subcategory of this is DPS, or how much damage the weapon can deal every second, which is affected by your fire rate as well as the base damage score. A slow, heavy sledgehammer might still have a higher DPS than a small pipe pistol because even though the pistol is faster the sledgehammer has a higher damage per hit. That's some nice RPG knowledge right there. You like that? Go play some World of Warcraft and get back to us.
Back to TopThis is how quickly you can get off shots or swing your weapon – melee weapons have a speed of Fast, Medium or Slow. Slower melee weapons tend to do more damage but you can leave yourself open while you're hefting it. Bosses that telegraph their attacks really obviously? Slow fire rate, mate.
Back to TopIf you're a bit of a pansy and you don't like getting in too close then go for range.This is how far your gun can effectively fire a bullet, so rifles, for example, will have a higher starting range than pistols. If you increase your gun's range then it will have better accuracy at distance both in and out of VATS.
Back to TopThis, obviously, affects how likely you are to hit something you're aiming at, even if it's the side of a barn. Increasing your accuracy score can drastically improve your chance to hit in VATS, and will give you more focused aim when you're using your gun in the wild.
Back to TopWe're not going to dignify this entry with an explanation of what "weight" means.
Back to TopAlmost all the guns you'll pick up will share the same mod slots, so we've broken down how these change a gun's stats when you're tinkering with them. The exceptions are energy weapons which have a couple of slightly different slots, although we've got your back and covered them with the other mods below.
Remember that although you'll instinctively want to stack high damage sometimes that's not always the best choice when you're choosing between mid-level modifications: a sniper might want to keep more range, for example.
Back to TopUpgrading the receiver affects a gun's damage and rate of fire, and, in some cases, accuracy and critical shot damage. For some weapons a new receiver can also modify the ammo caliber of a gun (a .50 caliber will do far superior damage to a .38, for example).
On laser and plasma weapons this slot is replaced with the capacitor, which changes damage, ammo capacity, and critical hit damage, as well as potentially adding additional burning damage to your shots.
Back to TopDifferent barrels will adjust the sighted and hip-fire accuracy on a gun, as well as recoil and range. Generally superior range and sighted accuracy means sacrificing some hip fire accuracy. Gamma guns have a dish instead of a barrel, which you can beef up for more range and damage.
Back to TopThese, as you might imagine, mostly improve your recoil and aim with sights and scopes. Larger stocks will sometimes give you a bigger wallop when you smack an enemy with your gun (or, as the game puts it, "improved bash").
Back to TopThese change your ammo capacity and reload speed. Some larger magazines have a slow reload, but the top tier Large Quick Eject Mag gives you both.
Back to TopSights improve accuracy. Obviously. There are a few other things to take into account, though: some improve focus and sighted accuracy, while actual scopes can have different levels of magnification. Some add night vision, and a Recon Scope will add a tracking marker to an enemy you've targeted, so you always know where they are.
Back to TopMuzzles reduce the range of your gun, but in return you get better recoil or, if you choose to add a bayonet, a gun you can stab people with. You can also affix a Suppressor as a muzzle, which is a silencer by another name. On a minigun you can add blades to the spinning barrels so you can blend while you shoot. Very convenient.
Back to TopGun Nut (which goes up to rank four) will take care of your standard pistol, rifle, and heavy gun modifications. For the high-tech energy weapons (laser, plasma, and gamma guns) you'll need the Science! Perk. These are both predicated on Intelligence, but Gun Nut needs only a lowly three points of it, whereas Science! needs you to have at least six points of standardised smartness. If you're not investing that far into intelligence but still want to use guns then ditch high-tech weapons, because you're probably going to level past them quickly.
Back to TopGears, oil, and screws are your go to, as well as some aluminium or steel depending on the mod. Steel in particular is very common; it's basically a tripping hazard, but you can check out our more detailed guide to finding components for the others.. You'll also need adhesive for almost all of the mods, and you can farm your own supply, but if you're not the settlement building type then pick up loads of Wonderglue and duct tape.
Scopes will need a little bit of glass or crystal for the, you know, scope part, and glow sights need a bit of nuclear material – you can get that from the Blast Radius Board Game or biometric scanners. Killing the squisher, glowier ghouls is the more messy option.
Back to TopIt turns out that melee weapons are some of the most creatively evil in the entire game. If we listed every single melee mod option it would be a really long list and you wouldn't be arsed reading it, so we've split them into blades and blunts. These mods all principally affect damage and weight, because when you're close enough to hit them who needs accuracy?
Back to TopOn swords and other knife style weapons it's mostly just changing the stabby bit itself (for example, by adding a Serrated Blade), and in some cases you can even electrify the blade, although it seems like that would be a recipe for hurting oneself. Rippers, the horrible little hand-held chainsaw things, can have their blade modified to increase damage and add bleeding or disarming options.
Back to TopModifying blunt weapons involves gluing stuff like steel and concrete on them to add more and different types of damage (crippling, bleeding, limb damage and so on). You can wedge bits of steel into a pipe wrench grip to make smacking someone upside the head even more horrible: a hook for disarming, a spike for armour piercing, a load of screws to cripple and deal extra limb damage. The same sort of thing applies to pool cues, pipes, and baseball bats, which come chain wrapped, bladed and barbed, amongst others.
Back to TopAll you really need from the Perk chart is Blacksmith, which eventually gives you access to all the melee weapon mods. This requires a strength stat of at least four, but since melee weapons are usually the favourite of characters on a strength build we'll assume you're alright there.
Back to TopAs we mentioned, a lot of melee mods are sticking even more sharp bits of metal on to whatever you've chosen to hit and/or stab people with, so you need adhesive and steel. Some of the more advanced melee mods require you to toss in some aluminium or oil, or, occasionally, fibreglass (which you can find pretty easily in boxes of Abraxo Cleaner).
