Would help if you specified the rifle type and usage. Mag feed, single shot, etc.
I just swapped from 338 Lm to 300 norma. So far so good. Peterson is getting pretty close to releasing brass too, which should improve on the norma cases.
30-338 What? If you are talking Winchester and you already have the rifle, I don't have any suggestions. If you don't already have the rifle, my suggestion is to chamber it for a 308 Norma Magnum.
^^^What he said if 30-338 win. I shot a 30-338 win for years just to get the longer neck. Simple neck down of .338 win brass. Same thing can be accomplished with .308 Norma. Many would argue the short neck on the 300 win doesn't mean squat so just stick with a 300 winny.
I shot the .30-338 for years as my 1,000 yard "any-any gun". I went with this cartridge over the .300WM because Sierra loading manual stated that the.30-338 would shoot 200gr match bullets 100 fps faster than the 300 WM. Kind of a silly reason to go this route but the cartridge is easy to load and is very accurate.
My personal feeling is that it has a slight advantage over the .300WM with heavier bullets but I doubt I could prove this and I not sure that anyone will notice much of difference between the .30-338 or the .300WM.