Code guru help.
While visiting our daughter near Aledo, Texas, I saw something I'd never seen or even thought of before. My SIL and I walked down the street to a new house under construction. The electrical was being roughed. The electrician was in the process of connecting the bond from the main panel to the ufer. He stripped all the insulation off an 8' piece of 12/3 w/ground and attached each of the four bare wires to one of four screws he had put on the side of a stud (about 1/2" apart). Then, he straightened them out chucked them into his cordless drill. Ran the drill and basically ended up with a four stranded wire. He used that for his EGC. I tried to look it up when I got home and see if anything would prohibit this. I couldn't find anything. But I figure there's a rule somewhere that I'm missing.
I did note that 4 #12 is pretty much the equivalent of a #3.