Nano Packs are one of the most powerful items in the game, and are always highly sought after. They are a part of some of the strongest assemblies in the game, and can functionally give you infinite ammo for most weapons. Despite this, seemingly no player fully understands how they work as I've talked with players from top skill all the way down. There are a few reasons for this though as Nano Packs work somewhat unintuitively where you would only understand it if you've delved into the code. They also tend to be used for assemblies and not really focused on what they individually do. Finally, they are also rare enough that most players never find more than one in a game unless they're playing Angel of 100 or Archangel of 666. Because of this, I decided to explain the mechanics and details of them and how to best take advantage of its power.
Recharge Amount and Recharge Delay
First, items that recharge have two different properties which are the recharge amount and the recharge delay. Recharge amount is how much an item recharges on an action. For example, Blaster's recharge amount is 1, while Nuclear Plasma Rifle's recharge amount is 4. Recharge delay is how many actions have to pass before the recharging begins. For weapons, you have to not be firing, and for armors, you have to not be taking damage. For example, Malek's Armor has a recharge delay of 10, meaning 10 actions of not taking damage have to pass before it begins recharging durability. Nuclear BFG has a recharge delay of 0, so even after immediately firing, it already begins recharging.
Below are the following values for recharge amount and recharge delay:
Blaster - 1, 3
Nuclear Plasma Rifle - 4, 4
Nuclear BFG - 1, 0
Malek's Armor - 5, 10
Necroarmor - 2, 0
Nyarlaptotep's Boots - 5, 10
Tactical Armor - 2, 10
Tactical Boots - 2, 10
Power Armor - 5, 10
Nanofiber Skin Armor - 1, 5
One small detail is that the action must take at least 0.1s. If you have achieved a speed faster than that, whether it's moving, firing, or any other action, you will get a non-recharge action and get no recharge. There are only a few cases where this is relevant.
Nano Pack Mechanics
When it comes to applying a Nano Pack to an item, there are a few different checks it goes through before deciding what it does. First, the item is checked if it can already recharge. If it can, it will either reduce the recharge delay by 5, or if the recharge delay is already 0, it will add 1 to the recharge amount instead. If the item doesn't recharge, the Nano Pack will turn the item into one that recharges with a recharge delay of 5 and a recharge amount of 1 for weapons and 2 for armor.
For some examples, if a Nano Pack is applied to a plain Shotgun, it will become Shotgun (N) which has a recharge amount of 1 and a recharge delay of 5. If a Nano Pack is applied to a Blaster, it will reduce the recharge delay by 5, bringing it to 0, so your Blaster (N) will still have a recharge amount of 1, but have a recharge delay of 0 instead of 3. If a Nano Pack is applied to a Nuclear BFG, the recharge delay is already 0, so it instead will increase the recharge amount by 1, so Nuclear BFG (N) will have a recharge amount of 2 and recharge delay of 0.
The big appeal of these mechanics, and also very expensive, is when you begin using double or even triple Nano Packs on items. If you take a Shotgun (N), which has a recharge amount of 1 and a recharge delay of 5, and apply a second Nano Pack to it, Shotgun (NN) will have a recharge amount of 1, and a recharge delay of 0. As long as you don't encounter non-recharge actions, you can endlessly fire similar to Nano-Shrapnel and Nanomanufacture assemblies, but you have room for 3 extra mods instead of just 1 after completing the assembly.
Double Nano Packs and Triple Nano Packs
Let's look into various hypothetical items that can be created as a non-assembly with multiple Nano Packs.
Combat Pistol (PPPBB) is generally the cheap option for an extremely strong Pistol, but some players opt to go with Nanomanufacture Combat Pistol (P) for infinite firing and a little less power. However, you can instead go with Combat Pistol (PPPNN) which gives both the higher power while also being infinitely firing too. Alternatively, you could also go with Combat Pistol (PNNSS) to be able to fire infinitely and cancel accuracy penalties of distance and darkness. With Son of a Gun x5 reducing firing speed to 0.1s exactly, the additional speed multipliers of being a Scout or being Berserk can cause you to get non-recharge actions, but the natural clip of 15 is also helpful if you're getting these.
Plasma Shotgun has unique properties with a shotgun blast dealing Plasma damage, but can be very ammo hungry and doesn't fit well with Nano-Shrapnel assembly. However, if you were to make Plasma Shotgun (NNNPP) or (NNNTT), it would be recharging 2 ammo after each shot taking 3, giving you a full 30 shots of continuous firing even in the worst case scenario. This weapon is incredibly powerful at destroying corpses, walls, and has the best shotgun blast type, having the best range, depth, and lowest damage reduction. Multiple Nano Packs can turn it into a solo weapon instead of just a support.
Nano-Shrapnel Super Shotgun (P) is often viewed as one of the god weapons of the game, giving 6d4x2 Piercing damage that can be endlessly fired. However, Super Shotgun (NNNPP) also provides infinite firing with recharge amount of 2 and recharge delay of 0, and while being Shrapnel damage instead of Piercing, it boasts a massive 10d4x2, which is significantly more powerful that Nano-Shrapnel Super Shotgun and other variants. You could also opt to go with (NNNTT) for even faster firing and still higher damage with 8d4x2.
Rocket Launcher (NNFFF) allows for 2 extra Firestorm Packs over Nanomanfacture Rocket Launcher (F), giving a much larger blast radius. With the non-assembly, multi Nano Pack build, the blast radius reaches a massive 10, able to blow up a giant portion of each floor, while also being able to be fired infinitely.
Nuclear BFG (NNNFF) gives a recharge amount of 4 and a recharge delay of 0, meaning you can fire a giant BFG ball every 10 actions and melt everything. It's not as massive as the radius from Biggest Fucking Gun, but you can fire the non-assembly variant pretty repetitively. You can also go with a regular BFG (NNNBB) to have a recharge amount of 2 and recharge delay of 0, but holding a clip of 169 cells, letting you fire 4 consecutive shots and then being able to recharge for more later.
Laser Rifle normally fires far too many shots, but with the Marine's Ammochain firing only 1 shot per burst, Laser Rifle (NNFFF) becomes infinitely firing like Nanomanufacture Laser Rifle (F), but shoots out 4 extra shots per burst, giving a giant increase in damage. With Triggerhappy x2 and Son of a Bitch x5, you'll get 13 shots per burst, which you can endlessly shoot, each doing 1d7 + 5, giving a maximum damage of 156 and average damage of 117 every time you press to shoot.
As you can see, many of these weapons are ridiculously powerful, but of course come at extremely high costs that likely are only obtainable during Angel of 100 and Archangel of 666 games.
Medical Armor
Because Onyx Pack exists for armors, Nano Packs are inferior as you can have infinite durability instead of recharging durability. However, there is one exception to this with Medical Armor, as the healing effect from it comes from durability. Onyx Packs don't technically make armors have infinite durability, but instead hide it and skip the check when taking damage. However, Medical Armor healing doesn't do this, so you can still have your Medical Armor (O) drop down to 1%.
A single Nano Pack will result in Medical Armor (N) with a recharge amount of 2 and recharge delay of 5, meaning that you can let the armor recharge after healing you, but you have to finish taking damage first before it kicks in. There is a way around this however, with Nanofiber Skin Armor assembly made with Medical Armor, essentially giving you a Medical Armor already having a recharge amount of 1 and recharge delay of 5, and then finishing the item with a Nano Pack, giving a recharge amount of 1 and recharge delay of 0. What this means is that as soon as you take damage, Medical Armor will heal you like normal, but also immediately restore 1 durability. If you were to continuously be taking 1 damage, you can then immediately heal 1 damage, and the armor will self-repair for the same amount. This means you can find a nice pool of acid to stand in and hypothetically take infinite damage, possibly leading to adverse effects as the variable for tracking damage taken might either cap off, or possibly roll over back to 0. This could be an alternative way to earn Iron Skull instead of using Vampyre as well.
Outro
Hopefully with this information, more players will understand better how Nano Packs work and consider making some of the hypothetical weapons possible if they're fortunate to find multiples. I've requested that the Medical Armor exploit be fixed in a future version, with an easy fix of Nanofiber Skin Armor having a recharge delay of 6, preventing the value from reaching 0.