Understood, the barrel was just an example of parts that are QC'd. And, though I didn't mention it earlier, proper has port sizing is pretty paramount.
Yes, port sizing would certainly be a much bigger concern in this application although it wouldn't be that hard to deal with unless it was grossly out of spec. I didn't want Excalibur to think he had to spend a lot of extra $$s on accuracy for a rig that doesn't exactly lend itself to the utmost accuracy. IMO, he would be better off spending the extra money on a quality BCG first with such a setup and a barrel second.