I'm sorry, but I found again how to make easy cash on crafting.
I hope you'll do something with it on next update, but:
I tested alot things, here's best results:
You need character with SG1 prof, then you can:
Craft Desert Eagle (Exp. Mag.) for 1 metal, 2 junks (1 for pistol, 1 for exp. mag) and 1 wood. Most vendors (the same, who were buying cartriges for 8 caps) will buy it for 550 caps. You can craft it very fast and alot per once, crafting CD almost nothing, like 2-3 minutes and upgrading deagle gives no CD on crafting, so, I think it's even better than cartriges before update, when it was required regular gunpowder!
Other way:
You need character with demo1 prof, then you can:
Craft Frag Grenades! 5 gunpowder, 2 junk, 1 metal. And you'll get 10 grenades, can't remember crafing CD. Each grenade = 104 caps. So you'll make 1040 caps per once. It's almost similar pre-update cartriges, but requires 2 junks, but gives on 240 caps more.
Also, why .44 magnum revolver requires on 1 metal part more than desert eagle, but it's price less on 70 caps?
And why not upgraded desert eagle has it's price on 170 caps less than upgraded, but for upgrade you need only 1 junk.
Can you calculate item prices/crafting requirements a bit more?