Rifle Cartridge Case:
The cartridge casings main function is to seal the chamber area of the rifle barrel preventing high pressure gases from getting past the cartridge case in the chamber. The reason for using brass for the cartridge case is that it will expand readily and make a seal.
There are two basic case shapes of brass cartridge cases, straight wall and bottle neck, the bottle neck cases neck and bullet diameter are smaller than the case body diameter.
The main identifiable parts of a cartridge case are: mouth, neck, shoulder, body, head, web, flash hole, rim and primer pocket.
In the head area of the cartridge case there are four designs and they are: rimmed, belted, rimless and rebated.
Rifle Cartridge Case Reloading:
The first rule when it comes to cartridge cases is never mix cases from different manufacturers or even same manufacturer with different lot numbers or batch run. If you really are looking for accuracy loads, bulk brass is cheap so when ordering order a minimum of 100 cartridge cases before standardizing cases.
Weighing Cartridge Cases:
If there is even 1/10 of a grain difference in weight between the cases that means there is a difference in the internal dimension and strength structure of the case. This will change stress expansion areas of the case which in turn will change the way the cartridge headspace's in the rifle chamber when it is fired.
Each time the cases are loaded and fired the heavier cases will stretch less between the cases shoulder and head than the lighter ones. Evidence of this can be noted by measuring case length after firing the cartridges, they simply do not stretch the same and this does affect accuracy.
The cartridge case capacity is directly affected which is nothing more than the volume of the cartridge case but of which in turn affects velocity hi-lo spread and will affect bullet impact or accuracy.
Case Neck Thickness:
RCBS CaseMaster® Gauging Tool.
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