for a hunting gun I would go with the regular 6mm-06 , no fuss with fireforming the cases , you can use Lapua cases that way you only have to spend $75 on 100 cases and those will last you the life of your barrel unless you get nuts with the pressures. The Ackley version will require fire forming and the shoulder angle doesen't do much good for the feeding from the mag and the added velocity would not be worth the hassel in my oppinion.
Myself and several other guys I know have found the realy heavy 115gr class 6mm bullet to be very finikey and some guns just will not shoot them , I'd get a 1-8 twist barrel and plann to shoot the 105 class match bullets like the 95 and 106 Bergers , 107 Serria Match King , 105 A-max. I would not bother with a tight neck chamber mostly because if you use the 30-06 cases necked down the necks will get thicker and may end up needing to ne trimmed anyway so you will get the benifit of the tight neck yet maintain nice thick necks , my 260 is like this when i use 308 cases.
One note though , you will likely find that these bullet don't realy like to be pushed over 3300 fps so you will probably be running mild loads to get best accuracy. I have seen guys be happier with the 243 and 6mm Ackley than with the 6mm-06 just cause the accuracy nitch was closer to the top of the pressure scale.
