They WILL headspace on the belt but
The history of belted cases is that they were developed back in the day of nasty powder and corrosive primers for rifles used in damp dirty places (Africa and India). Chambers were often dirty and/or corroded. Cases that headspaced on the shoulder could fail go chamber with bad outcomes for the hunter. H&H in their genius, came out with the belted case to allow headspacing while allowing the case body to be undersized and the shouder to be set back. As nobody reloaded back there back then, the stretching and swelling of the case was not a problem. Fast forward to modern times. Chambers, powders and primers are all clean. Belts are relics and not needed BUT ammo manufacturers still rely on the belt for headspacing and the cases are still undersized and the shoulder too far back. Easily fixed by necking up new cases, say 300 Winmag to 33 caliber. Then neck down to 30 but not all the way back. You want to create a false shoulder for the case to headspace on. Bolt should close with some effort. Then when you shoot it, the case is fire formed, fitting the chamber perfectly. This method of case forming is hardly "new news" and can be found in hand loading texts back to at least the 1920s. While I am not "in charge", I have been handloading for almost 60 years and own/have owned many rifles where cases had to be "made". I hope some find this information useful to extend case life in belted cartridges used in bolt action or single shot rifles.
