Thanks to a lead from Don here, I was able to procure a sizing die from a seller on a different forum. The 450/400 3-1/4" case is based on the 450 3-1/4" case, and has not been too tough to shape in my RCBS single stage...up to a point. I am able to get to within a quarter inch of the final form, and then no matter how much lube, no matter how hard I press, nothing. Any suggestions? Thank you!

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