9mm Super Cooper

[mikeone]

With the demise of 9x23 Winchester brass I was thinking of cutting down 5.56 .223 brass, When I stumbled upon the

9mm Super Cooper developed by Jeff Cooper doing just that.

Any of you fine gentleman have any info an this puppy?

Thanks Mike

[Guy Neill]

My recollection is that it is the 223 case cut to 38 Super length. May need to ream to allow the bullet to be seated and keep the mouth from bulging. It dates back to about 1972 or thereabouts.

I hadn't heard of the 9x23 Winchester cases being discontinued - where did you see it? Is this both from Winchester and Starline?

Thanks.

Guy

With the demise of 9x23 Winchester brass I was thinking of cutting down 5.56 .223 brass, When I stumbled upon the

9mm Super Cooper developed by Jeff Cooper doing just that.

Any of you fine gentleman have any info an this puppy?

Thanks Mike

[mikeone]

Just the Winchester stuff.

[PINMAN44]

Winchester still sells box 9x23.

[wide45]

You would be nuts to want to make any quantity of .38 Super Cooper.

Trim, and ream every case. Would be like making .44 Automag from .308, except smaller.

Base of .223 is smaller than 9mm's Case life is not going to be good in 9x23 chamber.

Edited November 19, 2008 by wide45

[Rabe]

Maybe showing my age but, when the articles came out about cutting 223 cases to fit the chamber on 38 supers to overcome the headspacing issues I did

cut, ream and fire formed about 150 cases. they did work but internal capacity was less so powder charges had to be reduced. The other problem was having

cases that were lopsided since the base of the 223 was smaller than the 38 super. Getting the case mouth expanded evenly was a problem. And yes I also

had an auto mag and made hundreds of cases for it from 308.

[buddy_fuentes]

I don't know about Winchester, but Starline still sells 9 SuperComp which is 9x23. I have 3 9x23 pistols and it is a great cartridge. I hardly ever shoot them...maybe I should start.

Buddy

[Front Man]

My recollection is that it is the 223 case cut to 38 Super length.

You are correct!

FM

[BOGA]

I use 9SC from starline. They are the same. Do you want to use only Win 9x23 cases? Its still available.

[eerw]

you can find the brass on gunbroker right now...

Winchester use to make limited runs of the brass..

I had 3000 pieces and over 3 years of shooting 9x23 in my open gun..I only used about 1000 pieces of it.

[gm iprod]

We just recieved a shipment of Winchester 9x23 to my gunshop. A little later than I ideally wanted but they are finally here.

Starline still lists as per above posts. I called them last month and they have no plans to drop this cartridge.

[9x23]

Information on the original Win 9x23 brass, for what it's worth.

The rim diameter of win 9x23 is larger than starline. (CP is also)

Starline 9sc and 38sc can use the .223 shell plate on dillion presses and

win 9x23 can't.

Win 9x23 has a thicker case wall. (Won't hold as much powder as 9sc)

This info applies to the old win 9x23, it's possible new stuff could be different.

I switched to 9sc years ago and don't have any newer win 9x23 to compare.