You want to use a 338 federal to seat the heaviest bullets. Wouldnt' the recoil be a little high for a F class rifle? I was checking the recoil for a 338 win mag and then I just imput the data for what I would guess a 338-06 improve would do compared to a 338 win - I was guessing at 2250 fps w/ a 300 gr bullet. A 12 pound rifle will still kick at about 23 foot pounds - about midway between a sporter weight 300 WSM
- and 30-06 shooting 180's. Even if you bump the rifle up to 15 pounds it would be stomping around 19 footpounds - more like a sporter 270 shooting heavy bullets. If you could take the punishment, your on to something. What about just taking a 308 and pushing a 240 smk through it??