What are some ideas for a wildcat based off the 338wm. Was thinking of a 270/338 or a 6.5/338. I have a mag Mauser action, like the short 338 case and already have a 338-06AI, and a bunch of 30 cal mags and improved.....

A 6.5/338 is a 264 Wmag. 7/338 is a 7mmRem mag. 416 and 375 are Taylor or Chatfield taylor. A 270/338 has been done already. I think it about 1 gr larger than the 270Wby. A 30/338 and 35/338 are basically a 308 & 358 Norma magnum.

the 338 win is a 2.5" case ..
22 is a barrel burner
6mm has been done.. see above
25 is 256 weatherby
6.5 is 264 winmag
7 is 7remmag
30 is 30/338 or 338 norma
8mm is the 8mm PMM
35 is 358 norma
.366 has about 10 versions
375 is 375 taylor
416 is 416 taylor
458 is 458 winmag
475 is an orange in a sock

270? there's not really a commerical 270x2.5 case, but the 270 weatherby is so close as not to matter

I realize that this is an old thread, but interesting all the same. I was loading some 338 win mags recently and got to thinking about possible wildcats on this case that might be worthwhile. The list in this thread is comprehensive, and does have some that I am considering, especially the 35-338. However, there is another one that really intrigues me...this would be the .400-338. The 416-338 seems to work quite well, so it appears to me that the 400 would be as well. I do know that there aren't all that many .410 rifle bullets around, however I really wouldn't need many. Plus, I could always plink around with 41 magnum bullets. I am just in the thinking stage now, and I have done some looking for info but haven't found anything yet-not to say that someone hasn't done this, I just haven't found them yet. I welcome any advice on this project and thanks in advance.