Firstly I am not real familiar with any of those cartridges/chamberings but my take on it would be.
Better range of higher bc bullets designed for game available in 6.5 mm
Better brass in a bolt action enabling higher pressures to be run? otherwise more velocity from the same case but with a smaller bore size is physically impossible.
On to the blackout...cant see how a 30 cal would chamber in a 22 cal but the reverse may be possible? in which case a low pressure bullet rattling down the bore should result.
Bookmarks