The rifle I was loading for came with a lee collet neck sizing die. I don't think this is a catalog item, but if you give them a call, they can hook you up. I also load for the 300WM. In simplest terms, the 30-338 is nothing more than a shortened 300WM. I ran the 7mm case into the 300 FL sizing die and expand it up to 308. No lube, no muss, no fuss. Then into the Collet sizing die, with the appropriately sized mandrel. If a die set came with the rifle, you have all the problems solved for you, I just use the 300WM die because I have it on hand, and I like to spend money on bullets, not dies. I was reading through an old publication about halfway through this project and came across one of Jim Carmichaels articles. He describes setting up stepped necks… leaving the lower half the larger fire formed diameter, and sizing only the top half of the neck. There are still some guys that do it, but its not the most popular technique now. Just to prove the feasibility of it, I loaded a few with my 300WM neck sizing die. Couldn't get the neck tension quite as high, but when using as a single shot rifle, it doesn't matter a bit. Again….$25 die set vs. $50-$75 set. There are plenty of great neck sizing dies out there, but most work best with lube. The collet die runs dry. Its just one more thing that gets me from the loading room to the range faster. My runout is .001 to .0015. Any 30 caliber fl die you have on hand with a tapered expander will work provided the shoulder is larger than the 7mm. 300WM, 300WBY, 300RUM, 30-378 ect….