I have a 336 that JES rebored/chambered to 356. I have played with 180gr bullets but couldn't get 280gr to feed. I sent some parts to Noneman and had them modified to feed a big/blunt boolit. I haven't tried it since but I'll get around to it. I set mine up "utilitarian" with a Ram Line stock set and a Holosight. Photo is before I put the holosight on it.
Yes, I've used 444 brass to make 356, but 356 brass is available every 18 months or so.
Where can I find a reasonably priced 275-300gr mold??