Re: .280AI vs. 30.06
I have played with the 30 Gibbs and really like its design. I only used 165gr SST due to barrel twist and recoil issues. At 1km, the 7mm 162gr mk were a much better bullet. The Gibbs was going faster then the 280 by about 200fps. Higher BC wins at long range.
If you want bullet weight, go 30gibbs. If you want less wind drift, go 7mm. If your hunting is inside 750yds on deer, it just doesn't matter. For longer ranges, get a bigger cased 30.
All the above caused me to build a 6.5-06 using 140gr SST's. Reason? This is going to be used for clear cut hunting where a long shot is 650yds, most are around 450yds. Wind is a big issue so very high BC is needed. Recoil should be moderate as I don't like hunting with muzzle brakes. Didn't want an improved case due to feeding issues.
After comparing the reg '06 family, I chose the 6.5 because of bullets - SST are amazingly long. Should have a higher BC then even the 142grMK or Lapua. The SST can also shoot in the .1's as proven in my Mytic wildcat.
Put the bullet in the boiler room and any properly designed bullet from 6.5 to 30cal will harvest the deer cleanly.