Bluing at 400F Cause your at 4000'....Strange the Colorado School of trades blues at 270F and they are over 5000'.
400 would ruin any receiver or barrel by quickly turning it red.
You must be mistaken. Bore plugs are dangerous and a waste of time. Bluing does not effect accuracy. Been there done that.
Lefty C
I agree that it doesn't effect accuracy but I plug anyways. My bore plugs can't blow out
