The middle rung: a pipe and some gun powder per pair, and no blueprint to research. For smoke you can craft, the hand-thrown grenade is the cheaper route.
The pipe is the odd part. Each pair carries a metal pipe, which puts smoke a rung above the 40mm shotgun round and makes it pricier than the round that actually kills. That same pipe would be half a rocket.
For most players the price stays theory. No player can craft or research the round, every one in your box came from loot, and there is nothing to learn. What the bill does tell you is what a recycled round gives back: some gun powder and, only now and then, the pipe.
Tip
For cover you can actually queue, learn the hand-thrown smoke grenade. It is a cheap Level 2 blueprint with no pipe at all, only powder and fragments. Keep the launcher smoke for the spot no arm can reach.
Questions
40mm Smoke Grenade ×10: how many resources?
Sulfur ×300, Charcoal ×450, Metal Pipe ×5.
Which workbench does 40mm Smoke Grenade need?
Workbench level 3.
How long does 40mm Smoke Grenade take to craft?
11 s for one, every step included.
How much scrap does researching 40mm Smoke Grenade take?
