I have been forming brass for a simple (200 thou shortened) 7mm saum wild cat using a form die with mutliple inserts

So far I have formed 40 pieces starting with new rem brass, (I assume the brass must be annealed from the factory) and running the die inserts sequentially over each piece. I had three pieces which I discarded that puckered out of the 40.

After forming and trimming I have to anneal before neck turning, otherwise I cannot get the neck turning expander mandrel into the brass to expand the necks or if I can get it in it springs back so hard straight away that I can't get it on the neck turner mandrel.

I am wondering if I will strike problems later on with shoulders cracking due to cold-working. Would I be better to anneal at an earlier stage, say after passing through two of the form inserts and then anneal again at the end? Having not done this before I am unsure of the best approach. Can anyone advise?

I'd anneal after the first two formings. If the metal has gotten that hard, best to keep it soft or you'll get splitters-- as you are seeing. I do like the looks of that round: Short and with a long neck. Perfect for a benchrest gun shooting those long-ogive, Berger VLD bullets...

If you've already formed 40 cases, why not turn the inside of the necks instead of the outside? Do you have an inside neck reamer?

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No i don't have any kind of inside neck reamer except for a donut cutter mandrel for my K&M neck turner. I thought that neck turning was more likely to give concentric necks and this had largely superceded inside neck reaming?

K&M sell expander that you should use before neck turning
http://www.kmshooting.com/pdf/25.pdf

Yes I use the K&M expandirion prior to turning but if I don't anneal prior to expanding the expander is difficult to pass through the necks and the spring back is so fierce and immediate that I cannot get the brass onto the neck turning mandrel.

Cheers

John

Had to ask. I normally use the K&M for the first cut and Hart for the finish or if if I just need to clean up necks. Hart uses a Expander button to match their neck turning mandrel.

Over the years wildcatting I have pretty good collection of neck turners/expanders from 17cal up to 30cal and I have few inside neck reamers. I shoot few tight neck rifles also.

Depending on spring back amount I've even used the expander from a FL die or might expander neck up a caliber. Just different way to do things not that what I do is better and I'm lucky have a friend with a lathe.

Good luck

Please tell us about this set-up. Who makes the "funnel" or "radiused" forming bushings? I wanted something like this for my wildcat. Not knowing these exist, I went with dedicated forming and reloading dies designed and manufactured by Hornady. Not cheap, but very high quality. Can your bushings handle the .532" head diameter? I have a set of bushing dies that won't. Mine are limited to the .473" head. They just crush the shoulder on a 300RUM. I have no need for them; would like to sell them. There is a place called Drill Bushing Warehouse that can turn bushings to design, but they are about $80 each (set-up and production). My Hornady dies were $400 for the five-die set, so it was a wash as far as money goes...

The die was built by Mark Spencer in Michigan you can contact Mark here. Mark was excellent to deal with and he does international orders (he sent the die to me in New Zealand). You would need to talk to him about the cost of specific projects but the die was $180US. It looks better in hand than in the pic. The brass that comes out of the die is straight and as concentric at the neck (after turning) as factory brass. There is a pic of some finished brass lower down in this thread, excuse my rough neck turning!
This die handles the .551 saum brass (widest point above the rebated case head) no problems. I think the die body was designed to support the case body to a degree during forming which probably helps.

here is a link to another die Mark made that converts wsm brass to long-neck saum brass. There are some good pictures of the die. This example performs a sizing operation on the case to account for the dimensional differences (wsm to saum) and it pushes the shoulder down so it is caliber specific and a nice piece of engineering.