Pointer needed to ream straight wall cases

[414gates]

I found this article

https://mdws.forumchitchat.com/post/...-walls-8072240



and I want to duplicate that for 458x1.5 cases.

Problem is I'm not entirely sure what I'm looking at.

I'd like to do this with a straight chucking reamer and a drill press. I've worked out that I can use a 0.452" reamer on a case that's been sized in a 375H&H sizer, and it's cheap to buy.

Any advice or info on reaming out cut down belted magnum cases using reamer in a drill press will be appreciated.

Addendum :

The chamber reamer measures 0.485" across the case mouth, so I'm assuming the chamber is at least that.

The brass wall is 20 thou thick at the 1.5" cutoff point.

A .459 bullet plus 40 thou doesn't fit in the chamber.

A sized case measures 0.469" at the mouth, so I think I can use a .452 reamer on the case held in the [ cut down ] sizing die.