Re: what caliber for long action?
Standard bolt face, 7mm: 280 Rem, 7mm-06, 7mm/270 (you get the idea for 7's) shooting a 162 Amax, 168 Berger, 175 SMK or 180 Berger VLD or VLD Hybrid.
Std face, 30 Cal: 30-06 with 208 Amax or 210 VLD's
Std face, 6.5mm: 6.5-284, 6.5x57, 6.5x55, 6.5-06 (not in any particular order, but I have a soft spot for the 06 case as a parent chambering). Load them long with a 140 Berger or a 130 or 140 JLK
Mag bolt face... yeah, anything in 6.5, 7, 30 cal using the bullets mentioned above.
I really don't think that a long action magnum is necessary for hitting paper and steel using a 6.5 or 7mm bullet. I think that a long action case is necessary in either Std or mag bolt face for 30 cal.