Just country . . . .
- Any fired case will expand to fit your chamber perfectly, as long as it isn't an extremely weak load.
- The reason that cartridges have body taper is to aid in extraction because the case expands with the chamber and the barrel does not reach yield like the brass does. After firing, And the chamber returns to its original dimension and the brass case is slightly larger than the chamber. The hotter the load, the larger the chamber increases in diameter when fired but the brass has exceeded its yield and becomes even tighter when the chamber returns to its original size causing heavy bolt lift.
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- Keep in mind that your chamber absolutely limits the amount of case expansion.
With normal loads this is for the most part true but not absolute because you still have to size the cases to keep them the same as the second firing. The chamber will still expand a small amount from the pressure
- The un-acceptable case expansion of belted cases happens during the reloading process.
I have never had belted cases expand during sizing, Only decrease in size
- Weakened cases expand more, and they can be reloaded many times.
Case expansion is caused by pressure and the alloy of the brass. And in fact a used case becomes tougher with firing and work hardens so it expands less than annealed brass cases or once fired cases no matter what the allow is. this is the reason at some point in the number of firings you have to size to some degree in order to be able to chamber the round without forcing it.
Belted cases have long been a problem for those that treat them like shouldered cases because of the dimensional differences in the two chambers and the loaded ammo.
The belted cases were designed to chamber in the worst environment for safety. And the differences in the dimensions of the loaded ammo and the chamber are as follows.
Belt diameters between the loaded ammo and the chamber are .003 thousandths different (Smaller)
Body dimension at the back of the case is .001 thousandths different
(Smaller) than the chamber.
Body dimension of the ammo at the body shoulder junction are .001 thousandth Smaller than the chamber.
The length of the case from the case head to the neck shoulder junction is .010 shorter than the chamber length and the main reason for the belt. To maintain head space. (And the reason that so many dislike the belted case) if they treat the belted case like a shouldered case and full length size it these dimensions will be present every time it is fired because they are using the belt every time and case life will suffer.
Case overall length of loaded ammo is.024 thousandths shorter than the chamber to allow for case growth when fired.
Once a belted cartridge is fired If it is to be used for dangerous game, it should be full length sized for safety. It is much better to sacrifice a piece of brass than a limb or worse.
If you want to use a belted case/cartridge for long service on big game that does not want to trample or eat you then size only enough to chamber and once it is fired you are no longer using it as a belted case because it is using the shoulder to head space on. When I hear of people using their belted case for 10 to 15 times, they have figured it out and are not over working their brass.
J E CUSTOM
