Well, I tried something that worked

on that rifle problem.

Little more on this gas block: the Superlative Arms gas block, first you open it up 18 clicks, which gives you a fully open flow through the port and into the action, then you adjust it down as needed to give you the ejection pattern you want, and it does this by venting excess gas out a port in the front of the block.  So it reduces the amount of gas going into the receiver that way instead of just blocking it.  

One thing advertised is that by doing that it's supposed to reduce fouling in the action, which has seemed to work.

You've got 30 clicks of adjustment, so today I took it down to a total of 28 clicks from open port, so it's venting a LOT of gas out the port.  And it worked, no jams or ejection problems.  Reduced it all the way, leaving one click(call it in reserve), and it still worked, full action cycle, locked the bolt on an empty mag.  Which seems kind of amazing, but at least for today it worked fine.

So that's the current status on this.  Total it's  a long path to here, and one of these days I'll write it up.

Note: I fired 17 rounds total today, and when I pulled the bolt carrier group to see about cleaning, it didn't need it.  Apparently all that vented gas took most of the fouling with it.

Added because I forgot it before, the instructions on this block in case you're interested