Hey banjoman, I've had a 338JDJ#2 for several years.
I've tried AA-2520, IMR-4320, IMR-4895, H-4895 and IMR-4064.
I've also loaded 180 & 200 grain Nosler Ballistic Tips and 200 grain Hornady Spire points.
The only powder I've tried that my barrel likes is IMR-4064 and it really likes it! Some of the other powders have shot groups or should I say patterns as large as 6 inches at 100 yards.
IMR-4064 is an MOA powder in my barrel with any of the bullets I have tried.
Hornady's Sixth Edition reloading manual has load data for the 338JDJ#2 in a 14" barrel Contender.
GOOD SHOOTING!
Slufoot