what benefits would a magnum primer have for a standard case?

[Boomer]

Did the cartridges have time to cool off outdoors for a couple hours before shooting?

The ammo was left outside overnight prior to the test.

 

[jsquig]

I've seen those pics recycled quite a few times across the web, and they seem to be more than enough proof for just about everyone who sees them, but sometimes a picture is not worth a thousand words. The pics don't capture the duration or temperature of the flame, nor the actual effect on pressure or "reliability" of the ignition with various powders. If that data can be paired with the pics, then that would be interesting. Has it been?

The other thing I question is the picture timing. Was this the "max" flame for all of the primers or just a well timed remington photo.... *tinfoil time*

 

[bigedp51]

The other thing I question is the picture timing. Was this the "max" flame for all of the primers or just a well timed remington photo.... *tinfoil time*

My apologies I thought I linked the photos, the first link is all of Germán A. Salazar's Articles and a lot of very good information. And the second and third links are the "source" of Germán A. Salazar's primer flash photos.

The Rifleman's Journal
Index of Articles
http://riflemansjournal.########.com/p/articles-index.html

Large Rifle Primer Study
A Match Primer Study in the 30-06 Cartridge
By Germán A. Salazar
http://riflemansjournal.########.com/2009/06/primers-large-rifle-primer-study.html

Small Rifle Primer Study
A Match Primer Study in the 6BR Cartridge
By Germán A. Salazar
http://riflemansjournal.########.com/2009/06/primers-small-rifle-primer-study.html

From the links above.

Primer Flash Photos
The photos of the primer flash generated by each primer type are quite revealing, showing us a range in flash size of several orders of magnitude among frequently used match primers. Upon viewing the range from tiny flash to near blowtorch blast, with much in between, we were encouraged that we had a lead on the search for the modern day incarnation of the elusive soft primer. At a minimum, the range of visual flash suggested that there should be significant performance differences among the various primers.

While each primer type is represented here by a single picture, five to ten of each type were fired and photographed. Within a given lot of primers, the visual flash of each type was found to be very consistent. However, different lots of the same type of primer can show marked differences from one another. The lots used in the testing were selected randomly from those available, some were relatively new and some were quite a bit older (up to 20 years) but all had been stored in a temperature controlled, indoor environment.

And what I want to stress is the Remington 9 1/2 and 7 1/2 primer photos. At our American Lake City Army Ammunition Plant, Remington had the contract to run the plant from 1941 until 1982. The Army liked and used Winchester ball powders in much of the small arms ammunition, and Remington had to light off the Winchester powders.

And that big monster flame of the Remington 7 1/2 primer comes from the picture below, and a bench rest primer.