Yes it would be a range as it is apparent the required volume ratio is very much dependent on the BB weight you are using.it's probably a range, 455ish being optimal and decreasing to 509ish before it really becomes noticable.
of course having said all that, for the 20 seconds when my mg42 was still an aeg it had no problems with accuracy whatsoever on a 650mm barrel......
Thank you for this. It made me smile after a difficult week dealing with UPS. I still can't stop smiling now.