Comments on: Cartridge Efficiency Basics from the USAMU

By: LouieLouie

LouieLouie — Mon, 26 Oct 2015 18:07:33 +0000

I think this webpage is a really good reference to start with: http://bulletin.accurateshooter.com/2014/03/overbore-cartridges-a-working-definition/

By: Just1Spark

Just1Spark — Sun, 25 Oct 2015 12:58:08 +0000

For those wanting a definitive list, you can easily look in one loading manual, and get a good idea of which cartridge is more efficient than another.
The easiest way is,
Given the same bullet and FPS, which one uses less powder to achieve said velocities.

This is only a start. But a good start.

The recoil of the 7mm Rem Mag is a good example of efficiency lost. If you can push the same bullet with a different chambering the same speed and less recoil, you have a more efficient cartridge there.

Would be best to only do this via the same load manual.

By: Guy

Guy — Fri, 23 Oct 2015 23:46:39 +0000

Nice artical! Now the 7mm Remington Short Action Ultra-Magnum has the new Sierra 183 grain with a .713 BC.

By: John

John — Fri, 23 Oct 2015 23:31:58 +0000

How about a definitive list of efficiency characteristics? They mention “short and fat” several times, but both the Rsaum and WSM are short and fat, and the Rsaum is said to be more efficient. which shoulder angle? Rsaum at 30, WSM at 35, the AI’s at 40? and of course, I’m sure with every cartridge different combinations will yield the greatest efficiency. I guess that is why you wildcat every new case design to come out, trying to find which factors work with that case. wish there was a simple answer, but that would take all the fun out of it.

By: Dave

Dave — Fri, 23 Oct 2015 22:47:27 +0000

Is there a definitive list? Is the 300wsm more efficient/accurate than a 300 win mag?