Bad mouth BELTED MAGS

[longwinters]

So why are belted mags often badmouthed?  Every so often I hear it or read it.  I understand some of the concepts; but say with the 7mm,  the belt seems only to be for looks "cuz it is a MAGNUM".  however my understanding is that the case does not ride on the belt  but rather on the shoulder.  Could someone relieve me of my ignorance in this area?   :?  

long

[KN]

A lot of people don't like belted cartridges because they are difficult to resize all the way to the belt. They tend to wash out in the corner after a few firings. You are correct that most rounds headspace off the shoulder but there are many belted straight wall cartridges. 450 marlin, 458 win mag. are two that come to mind. These would headspace off the belt, thus the need for a good corner.   KN

[Dand]

I think where people get mad at belted cases is a combination of occasional poor chambering (Slightly long) and the habit of full length sizing cases whch may bump the shoulder back a little.  The combination causes cases to stretch quickly and separate if over- used.  In a properly chambered gun the shoulder and the belt of the case contact the corresponding parts of the chamber at the same time and there is little stretching.  

The way to avoid problems in long chambers is to carefully size cases without setting the shoulder back.

I have a proberly chambered 300 win and follow the sizing practice above and have probably gotten up to 15 full power loads out of some cases - I used the same box of 20 shells for over 12 years and usually reloaded the whole box at least once per year.  Finally got some necks splitting a little and just figured it was time to retire it for new brass.