We're not the Avengers, but we can still assemble.

With my lower printed it's time to fit everything.  Everything in the CAD file is pretty much drawn to size, which means that in the physical print, everything has slightly too much material.  I'd rather have too much than not enough so I'll leave it like that, but it does mean that the lower will require a little fitting.  All the holes get cleaned up with appropriate sized dill bits, and any burrs or bumps where other parts fit need to be filed smooth.  I left the surfaces where upper sits on the lower slightly too big in the CAD so that I could get a perfect zero slop fit between the upper and lower(particularly in the buffer tower area), and that also means that there should be enough material to make it fit well with any brand of upper.  This makes it less plug and play than a standard AR lower, but the end result is a better fitting part.  I also slightly redesigned the trigger transfer lever to make it stronger as a printed part.  If it were made from metal, the original 1/4" x 1/4" size will still work fine.

With the lower assembled, I could mock up all the rest of the parts I have on hand.  I'm using a Bear Creek 16" stainless barrel, with a matching cheap e-bay muzzle brake(which may not do much, I mostly just like how it looks).  I'm using a Yankee Hill low profile gas block installed backwards so that the gas port on the barrel is covered(and the YHM was the cheapest one I could find).  A standard barrel nut holds the barrel on, and my yet to be designed handguard will clamp around it.  It will be a free floating guard, but if it seems like it needs support, I'll tap the tube hole in the gas block for a front mounting screw.  The scope is a 3x9 that my Dad had laying around, and the magazine is a 10 round AR Stoner(actually made by ASC, and reported to feed the 7.62x39 reliably).  I'm waiting on a set of screw together anti-walk pins for the trigger and transfer bar, and I still have a lot of work to do for the furniture, but it actually kind of looks like a gun now.