Firearm ammunition in Underrail comes in the following calibers: 5mm, 7.62mm, 8.6mm, 9mm, .44in and 12.7mm. They are all packed into a universal cartridge that any weapon class can use if the weapon is of that caliber. When crafting firearms, one of the components is the barrel which will dictate the caliber of the weapon. Not all weapon classes and models can use all calibers.
Three different types of ammunition are available for all calibers - Standard, expanding JHP and armor-piercing W2C rounds. Additionally, each caliber has its own craftable special round type. The value of different rounds can give a rough idea of their relative rarity and power.
You can mix and match different rounds of the same caliber into a single magazine using the Load Single Bullet options, allowing for additional tactical options and full reloads when less than one magazine worth of a single ammo type is available.
The cheapest and by far the most common variety. Has no drawbacks nor special strengths.
|Jacketed hollow point round.
Incurs 150% of mechanical damage resistance and threshold, but the damage that penetrates the armor is increased by 40% against organic targets.
Rarer and more expensive than standard rounds, JHP rounds are best used against soft, unarmored targets to cause extra damage.
|Armor-piercing cartridge with a tungsten carbide bullet.
Ignores 65% of target's mechanical damage resistance and threshold.
Rarer and more expensive than standard rounds, W2C rounds are best used against heavily armored or mechanical targets, such as auto-turrets and wheeled bots.
In addition to the universal Standard, JHP and W2C rounds, each caliber has a unique special round type. These can be acquired by reloading your spent casings with appropriate blueprints. There is a 30% chance to gain spent casing whenever firing a firearm.
Weight and value
Notably, 9mm JHP rounds are relatively cheap.
Bolts are the crossbow standard ammunition. They are not retrievable after use.
Crossbows also have a wide variety of special bolts available, which are utilities.
Energy weapons such as laser and plasma pistols use energy. Their internal magazines can be recharged with batteries. Energy weapons cannot be unloaded.