If I were you an wanted a big RN bullet then I would use a 300 gr. RN Woodleigh in the 338 you have..

I have shot a lot of stuff with it in my 338 Win. and it it a bit tough but I like that as I shoot buffalo with it, so I am sure it would work in your 338 and expand to the size of a half dollar and hold together, but you would get less penitration...

The 250 Gr. Nosler hardly expands in my .338 unless its on something really big, so it should be perfect in your bigger .338...