Topic: Terminology

[Scott Doyle]

Terminology started by Normand Gregoire
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Posted by: Normand Gregoire on April 29 2002,12:37

When looking at the base of a cartridge under the microscope, we see the top of the primer cup surrounded by a dark circular area, and then the surface of the case where is the headstamp.
Does anyone know a specific name for the dark ring around the primer ?  Thanks in advance.


(Edited by Normand Gregoire at 8:10 am on May 6, 2002)


(Edited by Normand Gregoire at 8:10 am on May 6, 2002)


(Edited by Normand Gregoire at 8:11 am on May 6, 2002)


(Edited by Normand Gregoire at 8:12 am on May 6, 2002)


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Posted by: admin on May 01 2002,10:41

The dark ring?  The primer is seated into the "primer pocket" and the ring is formed where the outer edge of the primer meets the edge of this pocket.  
Some manufacturers will use a colored lacquer primer sealant that sometimes will cause this ring to have a dark or colored appearance.  This is usually a deep red but other colors may be used.

Scott Doyle



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Posted by: Guest on May 05 2002,22:38

The "Ring" surrounding the primer may be one of three things:
(a) an optical distortion caused by the lighting and focal depth of the area being observed
(b) a circular "crimp ring" used in (military) cartridge cases to seal the primer in place,
© a ring of varnish of varying composition, used to (1) seal the cup to prevent humidity entering (2) to colour code the cartridge type or component type ( again Military).
As to © , the term is primer Annullus ( Latin for Ring); sometimes corrupted to "annalus "
Varnish compositions are important as they may form part of GSR, on either the gun or the person. Most varnishes are a Nitro- varnish base (quick dry) with appropriate pigment.
For meanings of varnish colours in Military ammo (British and German ) refer to collectors books on such cartridges. Coloured varnishes on US Military ammo have no differentiating significance (except maybe Lot-to-Lot inhouse significance).
Regards, Dr. Astrid M Vallati,  Brisbane


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Posted by: admin on May 07 2002,05:50

Annulus- as defined in the AFTE Glossary is "the ring-like space between the top of the primer and the primer pocket".
Thanks Dr. Vallati for posting your more specific reply!  I forgot to include the obvious term in my previous post.

Scott Doyle