The M4's bill to the last spring, and no blueprint to learn either. Airdrops and the Bandit Camp fill your box; this calculator prices what sits in it.
Two Spas-12s out of one airdrop is a nice problem to have. The recipe matches the M4's to the last spring, and this blueprint can't be learned either, so the bill only measures what a spare is worth as parts: four metal pipes, three springs and a good chunk of high quality metal.
Fight with the better one. Send the other to the recycler soon, while its condition is still high: a worn gun gives back less than a fresh one, and a Spas in full shape returns half its pipes and metal.
The one you keep runs on shells, and a semi-auto empties them faster than any pump. Queue a batch of buckshot the same evening. Fix it at the repair bench for some metal while you can: nothing you craft will ever replace it.
Questions
Spas-12 Shotgun ×10: how many resources?
High Quality Metal ×200, Metal Pipe ×40, Metal Spring ×30.
