Chantry,

Without an accurate mic or caliper to determine the exact diameters it is hard to determine if the interference is at the mouth or base of the cases. A swage die is not the proper method. The chambers are tapered and the brass cases should be tapered also( plastic cases are stepped). The Body of the CASE should be no greater than 0.854" (+0.0 -.009") at the base and 0.840( Z0.020") at the mouth. CHAMBER, 0.858"MIN/0.841MIN accordingly.
Mark one of the oversize cases with a sharpie pen. Tap it into the chamber and remove. The interference point will show where the marker is removed. Sand/polish at the interference point until the cases drop in.

John

Last edited by John E; 05/20/21 04:35 PM.