A friend of mine has a 408 (M310) in a McMillan A5 stock and a Night Force Scope......weight is north of 20#, it reminded me of carrying the M-60 back in the day. This said its a fun rifle to shoot but at $7per round you realy have to want to shoot it. He ordered a case of loaded ammo and has lot's of brass but the bullet selection is limited. I think the premium lathe turned bullets weigh 419gr and we chronoed it at just over 2900fps. We can not get a hold of any expanding bullets and it's not legal to hunt with solids in our state....none the less its an accurate rifle, we can consistantly get good results out to 1200yds, we have gotten hits to 1 mile but it should preform better but we have not had the time to stretch it out. As far as a hunting rig, its not really pratical 20#+ and a 30" barrel but it is cool to look at as long as you dont have to carry it around. With this weight and a the break the recoil is not bad at all. I did shoot it neeling without a break and it set me back a bit!!
For a hunting rig I would go with one of the 338 Mags, either the Lapua or Wby 33-378 if thats what you are looking for.