7mm SAUM from WSM brass?

[Varminteer]

Hello,
Anyone try making 7mm SAUM brass from any of the WSM family of brass?

Pushing the shoulder back in steps and trimming to length looks do able, I think! Base of the WSM seems to be a little fatter compared to SAUM.

I have not compared reamer specifications, etc yet.

 

[lurcher]

Why would you do this when you can just neck down/neckturn 300 saum norma brass

I have a 7mm saum-based wildcat that uses a form die to knock the shoulder down 200 thou don't ask me why I did it

 

[dannyjbiggs]

Hello,
Anyone try making 7mm SAUM brass from any of the WSM family of brass?

Pushing the shoulder back in steps and trimming to length looks do able, I think! Base of the WSM seems to be a little fatter compared to SAUM.

I have not compared reamer specifications, etc yet.

Hello there, Varminteer,

I've been doing just that since June 2011 for F-Class Open competition. In order to make a "cartridge" for reamer build, I actually pushed a .270 WSM case (later have used .300 WSM) shoulder back in a single step without any issue using a 7mm RSAUM FL sizing die with the de-capping pin assembly removed. However, I do not trim to 7mm RSAUM case OAL; rather, I keep the long neck. All of the WSM shoulder area that is laid down for "new neck" becomes one broad doughnut...not to worry, I have found it to be quite friendly. PROVIDED that I do not seat into it, but forward of it, which produces some cartridge advantages with the much longer neck.

You are correct that the new "wildcat" base will be of greater dimension than the standard RSAUM case (which shows up on the reamer print). Early on, I had John Whidden make a FL sizing die for me using the Kiff reamer print that I furnished. This was a simple, inexpensive die without a de-capping pin assembly, resembling a regular body die. (I believe that one of my Texas F-Open friends continues to use just a 7mm RSAUM FL die for his "gooseneck" formation?)

Danny Biggs

 

[Laurie]

However, I do not trim to 7mm RSAUM case OAL; rather, I keep the long neck. All of the WSM shoulder area that is laid down for "new neck" becomes one broad doughnut...not to worry, I have found it to be quite friendly. PROVIDED that I do not seat into it, but forward of it, which produces some cartridge advantages with the much longer neck. [Danny Biggs]

Wow, that's an interesting and I would think pretty novel approach! It obviously works fine too.

 

[Ken Dickerman]

Danny,
Presume you mean me. I initially used a stock 7 RSAUM FL Redding die to re size the Norma 300 WSM to a long neck 7 RSAUM. I am not sure it was necessary, but I rotated the case and re sized in 3 strokes. Too much lube creates shoulder creases. Later I obtained a Warner (work of art) FL re size die made from my fired brass and my reamer print. I discovered I could re size from 300 WSM to 7 SAUM in one go. I do trim the thick shoulder-now-neck after running a mandrel to push the extra brass to the outside. The trimmer REALLY bites when it hits this old shoulder now neck section. I have a superstition that the WSM is tougher than the SAUM and have had zero primer pocket problems to reinforce my unsubstantiated theory.
Ken

 

[Varminteer]

Thanks for the great information. Very informative.

I have 7mm and 300 SAUM brass for by rifle build but might experiment making them from WSM brass if I get my hands on some for a good price.

 

[dannyjbiggs]

Danny,
Presume you mean me. I initially used a stock 7 RSAUM FL Redding die to re size the Norma 300 WSM to a long neck 7 RSAUM. I am not sure it was necessary, but I rotated the case and re sized in 3 strokes. Too much lube creates shoulder creases. Later I obtained a Warner (work of art) FL re size die made from my fired brass and my reamer print. I discovered I could re size from 300 WSM to 7 SAUM in one go. I do trim the thick shoulder-now-neck after running a mandrel to push the extra brass to the outside. The trimmer REALLY bites when it hits this old shoulder now neck section. I have a superstition that the WSM is tougher than the SAUM and have had zero primer pocket problems to reinforce my unsubstantiated theory.
Ken

Yes, Ken, it was you! I thought that you were leaving them untrimmed, too, though. I should have mentioned that I use/used Norma brass. At the very outset, I first tried the process with Winchester .270 brass, only to find frustration and heartache. I tried many different approaches, but I could never push a Winchester case shoulder back without getting an accordion look!!

If you want to feel another type of bite, try doing an inside neck ream with a Wilson inside neck reamer after fire-forming and before trimming to 7mm RSAUM length! But, that was just another experiment that I did not adopt. I just shoot them in the condition formed right out of the die. My case OAL with Norma .300 is 2.090" after sizing, outside neck turning, and then trimming. It's about 2.088" with the .270 WSM due to the "necking up" feature. And, cartridge OAL with a 180 Hybrid is 3.261" with either case.

Without a de-capping pin/expander ball assembly involved, I find myself using a standard 7mm WSM "bushing" style neck sizing die on the forward portion of the "gooseneck" to best regulate case neck tension.

Dan