,308 brass to .358 question

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loooongshotz

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Good day.
Any tips, guidance, techniques or actual experience on .308 to .358 would be appreciated please and thanks.
On the same note, the best data is not "I heard, I read, I know a guy" etc., etc." The response that gets my attention, and that of others I'm sure, will be actually having "ben' there, dun' that" stuff. Pics would be great, but not a must.

Appreciate your time everyone.
 
I have done 30-06 to 35 whelen does that count?

I grabed a couple of pcs of brass that were range pickup ... so bad looking i would not reload them .... cleaned in side neck lubed
and tried to expand the necks.

worse mess you ever saw.... split.. top of mouth angled.. not centered

took 50 pcs of good brass and annealed them
low torch... held with fingers ... too hot drop in water

of the 50 I got 49 good nice looking brass ..... 1 split ...... hornady dies .... lots of lube inside neck
 
This will be similar to taking 30-06 up to 9.3x62, which I have done a lot of (as have others here).

What worked best for me was to expand up using a Lee .416 expander stem inside a Lee decapping die. I bought a set of replacement Lee stems for 416 Rem Mag and mounted one in the decapping die I already had. Easy.

Use a good lube - I use Imperial sizing wax. A small amount on the inside of the neck and Robert's your mother's brother. Annealing first will also help reduce losses.

Then, once you have them opened up, size them down in your usual 358 sizing die.
 
You "may" have to anneal. That process is well documented. If you split on expanding the necks, anneal first. If not a quick anneal of the necks after expansion may be required.

Expanding in steps is the best, and in my experience the LEE EZ X EXP works well for the task. Install a 338 expander in your die if it is a LEE, if not install it in a LEE decapping die. I grind off the decapping pin, but at the moment I can't remember why.

I like to shoot cast at reduced pressure in my 35 Remington. Doing so will set the shoulder back. I run a fired case over a 416 expander that I have installed in a LEE universal decapping die. This makes the case straight walled. I then FL the case set to give me the correct headspace. (Redding Competition Shellholder set helps). I've done this several times, annealing has not been required.

As above, lube the expander before installing it in the die, and lube the inside of the neck of the case before expanding it.

Federal brass is more malleable than another brass I've used.

Caveat: Proper headstamped 358 Winchester brass is available, that should be your first choice. If you choose not to, label your ammo box.

Hint: I carefully cut the glue seam on an ammo box, turn it inside out, reglue, and label with ammunition data.

zCQPHVzm.jpg


Relabeled and re-purposed 9mm Luger box.
 
I have converted lots of military 7.62 to 358. Did not anneal. I might have used a 338 or 8mm intermediate step.

The resulting 358 brass was shot and reloaded several times, without incident.
 
I run them through my 338 Federal die then my 358 Win die, lube the inside of the neck as well as the outside.
 
Lots of good experienced already posted here...

Anytime I'm making brass from a parent case I anneal. I've found it only helps with no negative side effects.

I just use a blow torch on low and a lee zip trim 3 jaw chuck holder in a drill.
 
I have resized many score of 308 Win to 358 over the past fifty years.

Rarely have a problem, no fire-forming necessary. Today, some 358 dies come supplied with tapered expander balls to faciltate this. One pass through the sizing die, prime, load, and head to the range.

Ted
 
I have made up different tapered expanders on my lathe for necking up. I drill and tread them so they fit the Lyman M dies. Total length of 1 1/2 inches with the upper section straight in the diameter required. You shouldn’t need to anneal the brass. The trick is to expand using an expander with a gentle slope. I have taken 30-30 cases all the way to 0.380 with no annealing.
 
When I was making .358 cases from .308, I used a tapered mandrel. I put this in my table top drill press, and held the case in my vise. A little bit of lube, ran the drill at high speed and the case neck opened up smoothly, and the mouth was even all around. Best thing was the heat from the spinning mandrel already annealed the brass. I loaded these at least a dozen times each with no case neck failures.
 
I have many .358 rifles and have never bought .358 brass. ALL YOU NEED TO DO IS run 308 brass into a .358 full length sizer, nothing else is required! I have done thousands and never had any kind of problem or failure, and have loaded many close to 10 times, do not over think it, it’s super easy.
Try 40 grains of IMR 4198 with the 250 Hornady SP always super accurate, and very deadly. The 358 is one of the best big game hunting cartridges ever developed.
Cheers and good shootin.
 
I run 308 brass into the 358 die strait up, lube the inside of the neck very well. I prefer to use factory 358 brass whenever possible.
I use IMR3031 with the 200gr Hornady sptz it is one of my favorite deer guns.
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