What makes a magnum primer different?

[Furncliff]

Primers Primers Primers, I have been finding magnum primers (small pistol) a little easier to find. What makes a magnum primer different?

Tom

 

[Eb1]

I may be totally off, but Heat(flame/burntime) and Cup thickness

 

[edelbrock]

You are correct. They have different burn characteristics and thicker cups.

 

[doubs43]

Magnum primers are designed to burn hotter than standard primers. They are necessary for slow burning and hard to ignite powders for a more consistent performance. Most manuals will show which loads were developed using mag primers.