I have been trying to eliminate all variables in my loading and technique. I try to put the exact same pressure on the plug when I tighten, snug but not crushing tight. I try and use the same number of strokes when swabbing and the same pressure when seating bullets. As near as I can tell the blowback is coming from both loc. When I stipped and cleaned the barrel/action there was blowback coming from the extractor channel on the bottom forward edge of the barrel.
I am thinking that headspace is an issue the same as a regular barrel or the 25 acp conversion.
I have not ruled out a bad scope as to the accuracy problems and will swap out a good known scope next time but this blowback is baffling me. I was really excited about how clean it was the first range trip.

Ethan