7mm Rem Mag case

Scotty454 · #1 03-01-2016, 06:54 PM

Just a question about the 7mm Mag case- what is the purpose of the band around the base? Is it for extraction, or strength, or...?

catnthehat · #2 03-01-2016, 07:02 PM

The "band" is actually what designates it as a belted magnum.
The belt is where the factory cartridge actually head spaces from.
Cat

Dick284 · #3 03-02-2016, 05:23 AM

It is an off spring of the 300/375 H&H.

The belt was provided on the parent cases to provide positive headspace due to the fact that the long low angle shoulder on the parent case didn't provide a good datum line that steeper shoulder angles do.

On cases like the 7 Rem Mag it's totally redundant as it's easy to headspace off the shoulder's datum line, but the cartridge design is set through a standard set by SAAMI, so that's what we've got.

Scotty454 · #4 03-02-2016, 07:26 AM

Thanks cat and dick, curiosity- satisfied.

Grizzly Adams · #5 03-03-2016, 06:12 PM

Marketing.

Griss