Gun Parts

A gun isn't crafted from ingots. It's assembled from machined parts, each made on the workshop machines and each made of whatever metal you chose for it. The gun's figures come from the parts you actually put in, not from the blueprint. A sloppy barrel makes a worse gun, never a refused one.

Parts can also be shaped from stock with a hand hammer on the Gun Table, at the standard dimensions of their variant (the barrel at its calibre class, a medium length and a standard wall); a machine then cuts them to any size: the drill grows the bore, the lathe thins the wall and the cutoff wheel shortens the length.

The parts

Every metal has these part forms. Each is made by one step on a machine, like any other form. A part is one item (a Gun Barrel, say) and the metal it's made of rides on it, shown on its tooltip:

Part	Made from	By	Work (Fu)	Steel
Gun Barrel	Turned Rod	Drill Press	6 + 1.5 × hardness	28.5
Receiver	Ingot	Drill Press	8 + 2 × hardness	38
Slide	Plate	Grinding Wheel	6 + 1.5 × hardness	28.5
Bolt	Rod	Grinding Wheel	6 + 1.5 × hardness	28.5
Trigger Group	Drilled Plate	Grinding Wheel	4 + hardness	19
Grip	Ingot	Lathe	4 + hardness	19
Sight	Plate	Rolling Mill	4 + hardness	19
Belt Feed	Plate	Rolling Mill	4 + hardness	19
Box Feed	Plate	Rolling Mill	4 + hardness	19
Cylinder	Ground Ingot	Drill Press	8 + 2 × hardness	38
Magazine Tube	Rod	Drill Press	6 + 1.5 × hardness	28.5
Suppressor	Cylinder	Lathe	4 + hardness	19
Muzzle Brake	Magazine Tube	Drill Press	4 + hardness	19
Eddy Sleeve	A conducting tube round the muzzle drags the bullet once it has left the barrel, and the lost energy heats the sleeve. Drains 50% of a magnetic bullet's energy at copper's conductivity (steel barely drags; a non-magnetic bullet only a tenth as much). Recoil is unchanged, so what it buys is a slower, quieter bullet: slow it under the speed of sound and the crack goes. Costs muzzle energy and 1.5× the drained share in extra heat.
Relief Vent	Nugget	Drill Press	4 + hardness	19
Barrel Shroud	Drilled Plate	Rolling Mill	4 + hardness	19

The cutting machines also have to be harder than the metal: the drill bit is 18, the lathe bit 20, the grinding wheel 30. So hardened steel (25) parts need a grinding wheel for every step, which rules out anything drilled or turned. Netherite (40) is harder than every cutting tool, so netherite parts can't be machined yet.

Grips from bone and wood

A grip carries no load, so it doesn't have to be a strong metal. The lathe also turns grips from:

From	Grip	Work (Fu)	Grip friction
Stick	Wood	2.5	0.4
Bamboo	Bamboo	3	0.4
Bone	Bone	5	0.5

Leather, wool, paper and honey can't be turned into a grip, but they can wrap one (see Assembling).

The barrel

The drill press makes a Gun Barrel by piercing a turned rod. A fresh barrel is a 3 mm pilot bore through a rod 30 mm across and 0.6 m long. It's nowhere near a gun yet. You cut it to shape, and each machine changes one dimension for as long as you keep it working:

Machine	Changes	Per Fu of work
Drill Press	widens the bore	+0.1 mm
Lathe	thins the outside	−0.2 mm
Grinding Wheel	shortens the length	−5 mm

The wall is what's left between the bore and the outside: (outside − bore) ÷ 2.

The machines don't know what you're aiming for. Drill until the wall is under 0.5 mm, or grind it shorter than 5 cm, and the barrel is swarf.

Work per cut is the machine's strength (St) divided by the metal's hardness. For example, a fast drill feed (22 St) on steel (15) is about 1.5 Fu a push, so each push widens the bore by about 0.15 mm.

Without Calipers a barrel just says "A bored barrel. Calipers would say how wide." With calipers in your inventory you get its bore, wall and length to 0.1 mm.

Hitting the target

The blueprint names a target bore, wall and barrel length (short 0.1 m, medium 0.2 m, long 0.4 m), but there's no tolerance check. Any barrel assembles. What happens is about how the cartridge fits:

A round will only chamber if its bore is within 1 mm of the barrel's real bore.
Too loose: gas leaks past. For every mm loose the round loses 60% of its energy (down to a floor of 30%) and spreads 3° wider.
Too tight: the round is squeezed. For every mm tight, peak pressure rises by 150%, which can easily take a gun into overpressure.

Get the bore to within a few tenths of a millimetre of your cartridges.

Assembling

Put the gun's blueprint and its parts on a Gun Table, in any slots: the parts decide the gun. You get the gun and keep the blueprint. The parts a gun is made of:

Part	Role
Gun Barrel	always; its variant is the calibre class; a second barrel only on a break action
Receiver	always; its variant is the gun's kind: handgun, rifle, shotgun, machine gun
Slide or Bolt	the action; its variant says which: self-loading or automatic (slide); bolt, lever, pump, break, self-loading or automatic (bolt)
Trigger Group, Grip	always
Cylinder, Magazine Tube, Belt Feed or Box Feed	optional: the feed (none means a box magazine on a slide; a bolt or lever with none loads one round by hand, and a Box Feed gives it a box magazine; a break action holds its barrels)
Sight	optional: a reflex sight or a scope (none is iron sights)
A fitting part	each fitting on the gun, one to a slot
Blocks of Redstone	a coilgun: two for the winding
A fibrous organic	wraps the grip

Each part's material is on the part. The barrel's metal and wall decide the chamber's strength. The rest add their own weight. A double's second barrel has its own metal and bore; two rounds in fires the first barrel, one round fires the second.

Wrapping the grip

Add any fibrous or sticky organic to the assembly (leather, wool, paper, honey) and it wraps the grip. Your hand holds the wrap, so the wrap's grip friction replaces the grip's. Kick goes down as friction goes up:

Grip surface	Friction
Honey	1.5
Leather, iron, steel	0.6
Bone, copper, wool	0.5
Wood, bamboo, brass	0.4
Bronze	0.3

Kick scales with 0.6 ÷ friction, so a bronze grip kicks twice as hard as a leather-wrapped one, and a honey wrap kicks at 40%.

Fittings

Optional parts change what a gun does. They are tip-like parts, machined like any other and added at the Gun Table (in the Assemble tab, or on a finished gun in the Rework tab). Each weighs what its metal weighs. A fitting may only change figures, only add a trait, or both.

Fitting	Effect
Suppressor	Report down to 35%, and sculk only hears it close by. Traps the gas's heat: the gun heats 1.6× as fast per shot.
Muzzle Brake	Cancels 70% of the gas's share of recoil (the gas adds a quarter on top of the bullet's). 1.6× louder.
Relief Vent	Opens at 90% of the chamber's rating, so the chamber never sees more than that: no overpressure damage, no blast in your face. Leaks 10% of every shot's energy.
Barrel Shroud	Fins: the barrel sheds heat 1.8× as fast.

A suppressor, a brake and an eddy sleeve all go on the muzzle, so a gun has one of them.

Changing a fitting

Add a fitting to a finished gun in the Rework tab. A gun takes one fitting to a slot, so to swap a suppressor for a brake, take the gun apart or swap the part in place with another of its own kind.

The chamber

How much pressure a chamber holds is the barrel metal's strength times the barrel's wall, divided by half the bore:

rating (Pu) = strength × wall (mm) ÷ (bore (mm) ÷ 2)

A standard round of gunpowder makes 3 Pu. So a 9 mm chamber with a 3 mm wall holds:

Barrel metal	Strength	9 mm, 3 mm wall
Netherite	50	33 Pu
Hardened Steel	35	23 Pu
Steel	15	10 Pu
Iron	8	5.3 Pu
Bronze, Cast Iron	6	4 Pu
Brass	5	3.3 Pu	barely
Copper	4	2.7 Pu	damaged by a standard round
Zinc	3	2 Pu	damaged
Gold	2	1.3 Pu	badly damaged
Tin	1	0.7 Pu	wrecked almost at once
Lead	0.5	0.3 Pu	wrecked on the first shot. Lead is for bullets

Halving the bore doubles the rating; so does going from a 1.5 mm wall to 3 mm. The other parts don't affect the chamber: they add weight and their own metal. A bolt action's lockup rates the same steel 25% higher.

Test commands

Operators can skip the shop for testing: /feedback build parts gives every part the held blueprint lists, and /feedback build gives the finished gun. /feedback barrel gives a barrel of any shape. These are for testing, not for survival.