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Type one is brass failure, often caused by mercuric-priming contamination or brass that is otherwise weak and brittle. Type two is excessive headspace in the gun. These result in different types of fractures. Type one (left)is a clean break with a crystalline surface. Type two is characterized by tearing of the metal and stretch marks on the case. UNDERSTANDING HEADSPACE In order for a cartridge to enter and exit a gun chamber it has to be made a little smaller than the chamber, with enough room for easy extraction after it is fired.

The quality of today's American-made metallic cartridge ammunition is superb. Nearly three generations of shooters have grown up since the last corrosive-primed, mercuric-primed, centerfires vanished into the mists of erosive smokeless powder, and not a moment too soon. Case failures with new commercially-made, centerfire ammunition is virtually nonexistent. It is in the business of reloading ammunition that most problems occur. Here the reloader (you) becomes the manufacturer and must become your own quality control expert.

Cartridge #2 is a low-density load with the bullet seated far out. The pressure generated would not be particularly high. Cartridge #3 contains the same load as #1 compressed by a deep-seated bullet. This would likely generate dangerously high pressure. Cartridge #4 contains the same charge as #2, but will generate higher pressures. Case-wall thickness affects loading density by increasing or decreasing the internal capacity: very critical when a maximum load is used. VENT HOLE SIZE A larger vent hole will affect powder burning rate by letting more of the primer flash pass into the case more quickly.