My full length resized .30-40 brass will chamber in either my school rifle or scout Krag but my segregated neck sized brass will not swap between rifles. The chambers are different enough to cause problems. My work around is to use neck sized .30-40 in the school rifle and use neck sized .303 in my scout. Neck sizing will lengthen your brass’s life. I was given a bunch of .303s during the drought and figured this would be a good way to use them. I don’t shoot the scout anymore though. Too many toys.