I think it's the other way around; 30 caliber's smaller than 33 caliber. But any full length sizing die with the same body dimensions as a smaller caliber one could be used on the smaller caliber case as long as there was enough neck clearance. It's happened for decades.So, a question regarding Redding die bodies. Would a .30-378 die work for a .338-378 since the neck is not being touched?
One guy that's shot on the US Palma Team has used a .358 Win. full length die as a "body" die on his .308 Win. cases. I've known some folks to use a .308 Win. full length die to "body" size their 7m-08 cases. And others have used a .30-06 full length die to "body" size their .270 and .25-06 cases. But they all had to be careful so the die's shoulder didn't touch the case shoulder else a step in the shoulder slope would happen.