I have both the 6mmAI & The 6/284 & love them both, 6mmAI 1-12 twist 87grn V-Max @ 3500fps & the 6/284 1-8 twist 107 smk @ just over 3200. Both shoot lights out & both have their specific uses.
If you BEHAVE yourself
the 6/284 will treat you very well; & if you don't, expect to have your bbl set back pretty dern quickly! I 'ersonally wouldn't recommend the WBY, I am kinda biased when it comes to that so I won't stand on a soap box here. Velocity potental is very close between the two although the 6/284 has a good bit more availability in the brass area.