The next step in 3d printing needs to be to make the rest of the gun parts instead of just 80% lowers, and also to making parts for things besides rifles and pistols. Imagine a 3D printer that could run off, say, the pieces for a put-together bazooka (fill the warhead with your choice of Fun Stuff) and a few claymore shells to go with your rifle.
Here’s a “for instance”.......the Upper on a Thompson (MiA1) is a massive, heat treated hardened hunk of steel that withstands continual slam firing (the firing pin is machined into the very heavy bolt). I just don’t see how current techniques can duplicate that.
Aside from the explosive filler, the primary component of an improvised Claymore mine is the 800 ball bearings that provide the fragmentation effect. These are a bit difficult to obtain locally in some areas and expensive for the prrpose to boot. However, stacks of ten glued-together pennies will do the job, with ten rows of ten each along the bottom-to-top rows and six or eight high along the sides. this works out to around six to eight bucks worth of pennies per unit, reasonable enough so long as production runs are small.
Oh, if you have trouble finding a blasting cap? Use an automotive airbag initiator, available *here* or at your local auto wrecking salvage yard.
Its still faster and more economical to machine most parts out of traditional materials