The HO guidance does say that good reason should not be equated to need, and that they should consider things primarily from the applicant's point of view. However it also says that just wanting to own a particular type/calibre of firearm isn't enough.
So in reality you'll need a fairly strong argument as to why foxing is a good reason to own a 6.5 creedmoor when there are plenty of "more suitable" options you could pick from.