An AK's bill minus the wood: 50 high quality metal, four springs and a rifle body. No blueprint can be learned, so every M39 came from a drop or a vendor.
Strip the wood out of the AK's recipe and this is what remains: the same high quality metal, the same four metal springs, the same rifle body. The row marks the M39 not researchable, so there is no blueprint to learn and the bill is only a price. It says the semi-auto from last night's airdrop holds as many parts as an assault rifle.
The recycler pays out the same way as for an AK, wood aside: half the metal, half the springs and a coin flip on the body. Its durability is lower than the AK's, so it wears out sooner in a long fight.
So decide by what the group lacks. Short on bodies and holding the AK blueprint, recycle it. Short on range, keep it and give it one of the burst modules your recycled LRs left behind.
Questions
M39 Rifle ×10: how many resources?
High Quality Metal ×500, Metal Spring ×40, Rifle Body ×10.