Small Primer Brass - Magnum or Standard Primer

[Allen One1]

Using small primer brass (6.5 Creedmoor) is there a noticeable difference between running a standard primer vs. using a magnum primer? Any testing out there on this?
Thanks,

 

[ReloaderFred]

Use the primer the loading data was developed with. I just finished reading an article on loaddata.com about switching primers, and what it can do to pressures, especially in high pressure rifle loads.

Hope this helps.

Fred

 

[Hondo 60]

Please, please, please use the primer the data lists.

In some rounds the pressure can be almost 2 - 3 times with a magnum primer vs a standard.

 

[ArchAngelCD]

There is no need to use a magnum primer in a case like the 6.5 Creedmoor. Magnum primers are only needed when large volumes of powder need to be ignited like in large belted magnum cases.

Just because the case doesn't accommodate a large primer doesn't make it less efficient.

 

[Allen One1]

Please, please, please use the primer the data lists.

In some rounds the pressure can be almost 2 - 3 times with a magnum primer vs a standard.

This is where the internet can get you in trouble. The 6.5 guys are recommending magnum primers in small primer cases. Then you get to thinking and off you go. I would rather stay with standard primers so I only need to stock one size and type for rifle.

 

[Allen One1]

There is no need to use a magnum primer in a case like the 6.5 Creedmoor. Magnum primers are only needed when large volumes of powder need to be ignited like in large belted magnum cases.

Just because the case doesn't accommodate a large primer doesn't make it less efficient.

Good point. Complete consistent burn of the available powder is what we are after.

 

[Sunray]

"...Magnum primers are only needed when large volumes of powder..." Nope. It's the powder itself, not how much that matters. Nothing to do with how a case headspaces either. Nor does the size of the primer matter. To magnum or not to magnum depends entirely on the powder used. Mind you, the help in extreme cold weather shooting too.
Using a magnum primer might increase pressures, but there are no lab tests that I've ever seen.

 

[ArchAngelCD]

"...Magnum primers are only needed when large volumes of powder..." Nope. It's the powder itself, not how much that matters. Nothing to do with how a case headspaces either. Nor does the size of the primer matter. To magnum or not to magnum depends entirely on the powder used. Mind you, the help in extreme cold weather shooting too.
Using a magnum primer might increase pressures, but there are no lab tests that I've ever seen.

I was talking about rifle cases, not handgun loading. In rifle loading it is the large volumes of powder that mostly dictates the use of a magnum primer.

 

[Demi-human]

With out personal experimentation and data collection, one won't know which of the above statments is false for their own rifle.

Creedmoor brass started out large primer, but I see that Starline now offers small primer brass, though thier flash holes are larger than sixty five hundredths. Small primer users will hope that a smaller charge of primer explosive will result in less variation of the powder burn and less disturbance of the bullet before the ignition. It seems counter intuitive to then use a magnum primer.

In a two twenty three I have found magnum primers to lower my E.S. and deviation. But I don't have the limitations of loading for competiton or magazine length. My bullets are firmly into the rifling and will most likely disassemble upon extraction. They will not however, move under primer burn.

Magnum primers do increase pressure. Priming pressure. Which is important for slow to ignite powders, powder that need more pressure to combust properly. As well as larger 'volume' cases, not so much the amount of powder, and in places that are very cold. A larger volume takes more gas to come to ignition pressure and cold powders will burn more easily at a higher starting pressure.
Whether this will put an established load over the pressure limits depends on application. Smaller cases will be more influenced by this than larger ones will.