Anybody tried building a .358 Win in an old Sako medium action. I have an old (60's) 243 that doesn't shoot so well and was thinking to rebarrel. Just worried it will not feed very well as I have another 579 in 308 that refuses to feed anything other than sharp spitzers.
If not - what would be a good action for a 358W

I shouldn't be a problem with that action. You should be able to go from any member of the .308 Win. family to another. My own .358 was built on a model 70 that was peviously a .243 and it worked out quite nicely.

I've got to agree that the .358 should be a real easy option for a L579. Perhaps the smith doing the work should give a look to why it currently isn't so smooth when feeding. Solutions might be quite simple here. I would also check and see that the follower isn't binding nose down. I have a 6/284 which feeds much better after removing the magizine box! The fatter cartridges need that extra room!