Help with resizing brass procedures

[Bill308]

Hello everyone, long time lurker here and this is my first post as I feel this forum is the best to have my questions answered.

I apologize if this has been covered time and again but I can't seem to find one place with all the information for what I'm looking to do.

I also realize this is a subject that could have many answers, but I'm hoping to find a consensus on what is the best way to resize brass.

To start off I think it would be best to explain my goal. Right now I am having my gunsmith (Mark Chanlynn) build me a custom rifle based on his Big Horn TL2 tactical action. I just sold a custom Surgeon rig that was chambered for 7mm WSM but I have decided to go with the 7mm RSAUM case for my new build because I think it can accomplish what I need with a smaller case and less powder. My goal is to shoot mostly 168 - 180 bullets from 2900+ with a 26" custom light Palma contour. I am pretty certain I am going to go with a 1:9 twist and am still pondering chamber dimensions. One other thing, rounds will be fed from an Alpha WSM AI style magazine which can handle up to 2.965 OAL.

Okay, here is what I'm hoping for advice on. Norma makes 300 RSAUM brass which I would like to get (if I can ever find any) and in so doing I will be resizing to 7mm RSAUM. I have tried to research the best I can to figure out what needs to be done and I've hit a few roadblocks that I'm hoping some of you might be able to help me out with.

As I understand it, this is what needs to be done:
[list type=decimal]
[*]Sort brass by weight
[*]Use FL (full length) die for 7mm RSAUM and resize 300 RSAUM brass
[*]Resizing has now created a donut at the case shoulder
[*]I am unsure of how to eliminate the donut, but I believe some neck turning techniques can do this, can someone explain how
[*]Use neck turning tool to ensure neck concentricity at 7mm - should I use case lube when turning?
[*]Finish rest of case prep process (e.g. primer pockets, chamfer, etc.)
[/list]

Is that it? Am I missing something? What dies would you recommend?
I have heard the Redding Trim Die 83280 is fantastic for this process, how best would this die be used? Are there any other tools or processes that would help me get the most accuracy out of what I'm doing, thank you.

 

[Varminator]

I'm assuming that the 7mm brass is not available. I recently formed some 6.5 x 47 Lapua from 6xc Norma brass just because I had some not because I needed it. Because part of the shoulder becomes the neck there are issues with the donut as in the donut from hell. Also after they are fire formed they won't bump until they are annealed.

In your case you are essentially using the parent case and are not decreasing the length. So the Redding form and trim would be your first operation then anneal then size then expand with a K&M expandiron then Neck turn to the appropriate size, shoot, size expand and turn again. I own several form and trim tools but didn't have one for the 6xc to 6.5 Lapua. I make 708 and .243 from LC military brass. I use graphite and Imperial wax for neck lube. For the annealing process you want to have a fast hot flame so as not to overheat the case. I quench mine but it is not supposed to be necessary.
Mark

 

[jonbearman]

After turning once and firing,does the neck have high spots or flow to remove.

 

[Varminator]

I do the same with dasher brass as well. The XC to 6.5 X 47 and .308 to 243 and 708 cases don't come around and stabilize until they have been annealed and turned and trimmed a second time after fire form. it is like there needs to be a way to relieve the shoulder so that it can then expand and fill the chamber. I thought about making a tool for this but I also don't have any reliable method of measuring the shoulder thickness. I need to get a lathe.
Mark

 

[Bill308]

Thank you for your help here. I hadn't seen anything about annealing after resizing so I will look into that. Do you all recommend a machine to anneal or do you simply use a torch and hand spin? From what I have read on annealing you want to be sure the heat is uniform. Also hadn't seen anything on sizing and neck turning twice so that is good advice as well.

Again, thank you all for your help as I venture out in this new world of resizing.

Bill

 

[Tim Singleton]

This is what I use to remove donut when making 260 AI brass
You outside turn necks at the same time if desired or just ream the inside diameter to get rid of donut
Neck turning mandrel with inside diameter cutter

https://www.kmshooting.com/catalog/neck-turner-tools/carbide-cutting-pilot.html

 

[amlevin]

This is what I use to remove donut when making 260 AI brass
You outside turn necks at the same time if desired or just ream the inside diameter to get rid of donut
Neck turning mandrel with inside diameter cutter

https://www.kmshooting.com/catalog/neck-turner-tools/carbide-cutting-pilot.html

Ever since I started using pilots that just cut out the donuts I've slept better at night

No more guessing how much shoulder to cut when neck turning, etc.

 

[Bill308]

This is what I use to remove donut when making 260 AI brass
You outside turn necks at the same time if desired or just ream the inside diameter to get rid of donut
Neck turning mandrel with inside diameter cutter

https://www.kmshooting.com/catalog/neck-turner-tools/carbide-cutting-pilot.html

That's brilliant Tsingleton, I had been looking at the K&M neck turner anyway and this just makes that system that much more ideal, thanks again.

Bill