July 7, 2004, 12:05 PM
Can someone explain the differences in primers, like Boxer, Berdan, etc...It is my understanding that this is related to corrosion, but I am not sure which is which.

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July 7, 2004, 12:39 PM
The boxer primer uses a single hole in the center of the primer pocket in the cartridge case and a decapping pin from a reloading press can press out the old primer for reloading.

Berdan has two holes in the primer pocket off center and cannot really be reloaded. Although every once in a while I supposed some one will try.

Americans adopted the boxer, which was a British design and the Euros adopted the berdan which was American by design.

The corrosion comes into play with the primer and or powder make up of the cartridge.

Alot of old milsurp was corrosive. After the 50's I think, most started using non corrosive mixtures but the primer styles still differ. This corrosive ammo was mostly berdan primed, thus the connection between the two.The date is not always an indication of whether it is corrosive or not.

Most all steel case ammo is berdan as is some brass.

If not sure of the ammo, ask the seller althought they sometimes don't know or won't tell you. If in doubt, wash the gun barrel and gas port system if the gun has one with soap and water and dry and oil right after firing.

Corrosive milsurp ammo is cheap and okay if you clean right away.

Mike Hull
July 7, 2004, 12:41 PM
Berdan primers were the invention of an American, and are used primarily on European ammo. The brass has two flash holes, neither centered, making it hard to deprime, unless you use hydraulic methods.

Boxer priming was invented by a European(English?), and is used in American ammo. Has a central flash hole convenient for depriming.

That's the short version anyway.

J Miller
July 7, 2004, 12:48 PM

To make it as simple as I can:

A boxer primer has three pieces. The cup, the anvil, and the priming compound.

A berdan primer has two pieces. The cup, and priming compound.

When seating a boxer primer it is a self contained unit. Seat it to the bottom of the case and it's ready to use.

The berdan primer works the same way, except the anvil part is built into the bottom of the primer pocket. Seat the primer and it's ready to go.

With either design when the firing pin hits the primer it smashes the priming compound between the cup and the anvil, firing it.

As for corrosion, this has nothing to do with the boxer or berdan primer designs. But it is dependent on the chemical compound of the priming mix.
There are corrosive and non-corrosive primers in both boxer and berdan designs.
Most, if not all currently made commercial ammo is non corrosive reguardless of primer design. I've read that some backwoods European military ammo is still corrosive, but I can't verify that.

I would suggest you go and look at some reloading manuals. Read the sections on primers. They will usually have pictures of the various different priming systems.

Hope this helpes a bit.

(I type too slow. In the time it took me to type this out, two guys beat me.)


July 7, 2004, 12:52 PM
Thank you questions are answered!

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