From: andrew, [EMAIL PROTECTED]
> I suspect part of the difference in case life is neck
> annealing and work hardening of the entire case. RG
> ammunition always shows a very marked amount of heat
> treating at the shoulder.
Actually all cases get heat treated the same. The difference is that the
military insist that discolouration from the final neck anneal is kept
so it can be seen that it has been done, whereas for commercial sale the
cases are polished bright because we like to see our brass nice and
shiny.
> Another point with Berdan primed cases is that the case
> forming (stamping) and primer pocket/primer hole(s)
> formation is done very differently. I was led to believe
> that such a system led to thicker case walls at the base
> of the cartridge and a thicker casehead.
The military specify a beefier case head and web because of the extreme
stress that these parts go through during extraction and ejection,
particularly in automatic weapons.
For further information I recommend the book "Ammunition making"
published by the NRA (of america) and available from
<www.discountgunbooks.com> and other book sellers. This book is a very
good read and is basically the biography of an engineer who worked in
the ammunition industry all his working life. Every facet of commercial
ammo manufacture and testing is covered of all types of small arms ammo.
--
That first point was an interesting tidbit. I was wondering
why Swiss GP90 has the discolouration at the shoulder of the
case but the commercial Swiss .223 doesn't even though the
cases are otherwise identical.
Steve.
Cybershooters website: http://www.cybershooters.org
List admin: [EMAIL PROTECTED]
___________________________________________________________
T O P I C A The Email You Want. http://www.topica.com/t/16
Newsletters, Tips and Discussions on Your Favorite Topics
