assuming this is directed this way.
,,,as good a platform , reamer modification start point,....might be as good a place as any.
The cartridge design I'm suggesting does NOT need a custom reamer, and in truth, I'd rather just as soon be putting a depth stop on a common, VERY affordable chucking reamer, and THEN dealing with concentric throating,....per normal , everyday, concentric lead bullet practice. Rim recesses can be cut with boring bars,....hell in ACCURATE rifles, they SHOULD be.
The WALL THICKNESS implied by the phrase "Everlasting" pretty much dismisses concerns about "taper" ....straight walls will work just ducky.
GTC