Yes, I did get your USB a while back, many thanks for that AND that wonderful thread on building a stock from scratch with hand tools. Very nice to see the whole process and you deserve the many thanks given for taking the time to post that information. I remember the issue with that barrel and the crusty lathe you used to fit the new one...that was interesting as well!
I've built AR's for awhile now, and worked on them for over 20 years in the military. I started doing barrels from the blank because the quality was somewhat lacking with any of the OEM and aftermarket stuff, and I do like a quality barrel. I've built AR's in many calibers, the 17 Remmy, 204 Ruger, 20 Tactical, 5.56, 6X45 (nice little caliber there!), 6,5 Grendal, 6X47 Lapua, 6.5 Lapua, 243, 260, 7mm-08, 308, 338 Fed, 358 Win, 458 Socom, 10mm Auto, and maybe another one or two I forgot... With the red locktite, be sure and face off the receiver if possible too. Just like a good bolt gun, a good square receiver face is important and most of them are definitely not square.
If you like cheap shooting and the 204 caliber performance, look at either the 20 practical or 20 tactical. I use the tactical, but to each their own. Dies are readily available and it is a VERY easy task of full length resizing once fired 223 or 5.56 brass and loading them up. Doesn't hurt a bit when you don't find all your cases. I would also expect very good accuracy from a well built AR. As I mentioned before, 1/2 MOA accuracy is well within norm for a quality barrel.
As for quality barrels, those Green Mountain 1.050" unturned blanks are a great value and offer some cheap options for less than $60 with a little extra work. I usually contour the blank within .010" or so, then cast a lap in the bore and finish lap the barrel. They clean up really well as the finish ream is very good on most of them before buttoning. After lapping I thread, chamber and finish contour the blank, cut, crown and drill the port. I made a few jigs to get the port in the proper location, and for a time even timed the barrel nut so the port would be in the center of a groove, but they seem to shoot either way.
Have fun and I'm glad I could offer some little information in return to all you've given to the trade.
Best regards,
Matt Salm