Seems my rifle is a fouler. I shot it at Bisley yesterday, 59 rounds down and it was orange (again) when I got it home.
300 passes with a nylon brush and two sessions with KG12 and it's gone. But 59 rounds to get it in that state suggests I am going to spend as much time cleaning as shooting...
I'm tempted to do an EBC clean, but tbh it's clean now, it's the rate at which it fouls that's the issue.