Ha! The next range trip things went south, back to back 5 shot groups just under 2moa...speeds increasing, 115 fps ES on 10 rounds. Round count 575 , and about 30 rounds since my last cleaning
I cleaned it with my typical routine, and borrowed a bore scope. It's pretty ugly in there!

- lots of carbon! 3 hours of trying this and that, I made some headway with CLR and bronze brushing / wrapping a CLR soaked patch around a worn brush and work it back and forth a lot. It wasn't all gone, but the carbon was way down over before.
Took it out and first 3 shot group was 0.7moa, next 3 averaged 0.59moa (80gr ELDm / RL26 in virgin Peterson brass) and speeds about 55 fps below what they were before. I shot four more groups with other ammo I had, avg group was 0.7moa - what a relief!
I took it home and cleaned with 3 wet patches of CarbOut and followed with about six dry patches to remove all the solvent. I took it out yesterday and shot four groups to assess any POI shift from the light cleaning. I was happy, POI from first group was within 0.25moa of the next 3 groups. Average group size yesterday 0.67moa with the 80gr ELDm load, and speeds were still down a bit - which is a good thing
Moving forward I think I'll run the carbout solvent through it more frequently to try and stay ahead of any excessive carbon buildup issues.