308 Norma Mag brass from 300 Win Mag

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hugh manuell

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308 Norma Mag brass is hard to find and very expensive, so I want to try making it from 300 Win Mag brass. I've read that it is a simple matter of running them through a 308 NM full length sizing die, then trimming to length.

I would like to hear from those who do it; any special tips/tricks? case lube? Does it take a lot more force than re-sizing the correct brass? etc. any comments welcome.

Thanks,
Hugh
 
I just found an orphaned Dominion 300 win mag brass out in the man shop.
Run it through my RCBS 308 Norma Mag full length die and no surprises.
I measured the case after this and found it to be 2.613" long.
Book value is 2.559" for the 308 Norma Mag brass length taken from one
of my Hornady reloading manuals.
I will post pictures later or tonight, time pending.
If I remember, I'll trim to length and see if the gal chambers in ole Shu$tzy.
Cheers.
 
Even easier is to use 338 win Mag brass. Just a tad short at the begining, but after very few firings you get the right lenght. As easy as resize, load and shoot. Depending on your load, you may even use your standard load for fireforming (Don't do that if you want to load HOT). This works for the .358 NM too.
 
Here's an update for you Hugh.....
I did find the old gal and chambered the sized 300 win mag.
A wee bit of friction on the bolt handle on closing.
The shoulder was a bit high and I think screwing the die down a tad
would cure this.
I didn't wish to mess with my die adjustment as it is set for my brass.

Some photos for viewing....

The orphaned brass before sizing.





The RCBS 308 Norma Mag die full length die.



Resized 300winmag brass compared to a 308 Norma Mag reload.



The measurement after going through the die.



Hornady's info page on the 308 Norma Mag.



The only improvement I could see on this proceedure would be to screw the die down a bit to lower the shoulder on the 300 win mag brass.
On the one photo comparison above, you can see the shoulder slightly higher than the reloaded 308 Norma Mag round.
I believe this was causing a bit of effort on the bolt.
I would suggest you size one and try chambering it in your rifle and adjust as necessary.
They end up being about .060" longer, so a bit of trimming is to be expected.
Cheers.
Looky.
 
Baribal said:
Even easier is to use 338 win Mag brass. Just a tad short at the begining, but after very few firings you get the right lenght. As easy as resize, load and shoot. Depending on your load, you may even use your standard load for fireforming (Don't do that if you want to load HOT). This works for the .358 NM too.
Click to expand...

That is exactly what I have done to form hundreds of brass for mine. Have also used 7mm Rem Mag, but it is a bit trickier to neck up than down, as the necks tend to form off centre.

Ted
 
Thanks again everyone, especially Kamlooky for all the research and photo posting.

I don't have a 300 Win Mag, but have some 1F brass on order fron the EE, so I'll give it a try in the near future.

Hugh
 
Well Hugh, I found, well begged/borrowed three more spent cases.
One WW Super, one FC and one ELD in 300 Win Mag.
I run them through the RCBS die.
I paid more attention this time to what the Rockchucker press was doing
with the feeling on the handle.
They were run through the press as I have them in order above.
The WW Super came out similar to the Dominion brass posted previous.
Here's the three bandito's on the lube pad.



This is the coal on the WW Super after the press.



Here are the three in order as above and you can see the neck on the middle one, being the FC not fairing so well.
I think the dent went through or close to it.



The one on the right (ELD)was the best of the four total.
This one I did a bit different.
Once I heard the spent primer fall out, I stopped the handle and pulled the brass out of the shell holder.
I then pulled the decapping pin and expander ball rod.
I ran the brass up again, but in stages and pulled and turned the brass.
Maybe five or six times.
The end result is very little damage to the brass.
Now to figure out what the ELD brass is?







The WW Super went through the press feeling quite normal.
The FC felt horrible, stiff and not smooth at all.
The ELD felt like Norma brass going through the press.
Soft and silky.
Those that have a keen feel on the handle will understand what I am trying
to describe.
Taking the decapper pin out made an improvement on the last brass.
Too bad I didn't have more to try out this theory.
Sum kibble for you Hugh.
Cheers.
Looky.
 
Looking at kamlooky's last picture, my very best result so far looks like the middle one of looky's. Most of mine are as bad or worse than the worst ones he showed earlier.

If I could get them like his "good" ones, I'd be happy as the proverbial pig.

I am using RCBS dies, RCBS lube and lube pad.

Hugh
 
I have made a lot of 308 Norma cases from 300 Win Mag.

A couple of tips: Do NOT get any lube on the case where the shoulder is or will be!!
{Imperial sizing wax is the best!!}

This will help eliminate the creases/dents at the shoulder of your new case.

New Winchester brass works best!! But RP is pretty decent.
I don't bother playing with Federal cases, since they tend to be on the "soft" side.

I trim to 2.550" after the sizing is done.
The cases will "grow" slightly on the first firing.

Regards, Eagleye.
 
Last edited:
Get yourself a decapping die from Lee.
Cheap and works well.
Take the decapping and expanding rod out of your RCBS die
and then run your brass through.
Once you have them sized up, put the pin/rod back in and run
them through again.
Might be worth a try????
Good luck.
 
kamlooky said:
Get yourself a decapping die from Lee.
Cheap and works well.
Take the decapping and expanding rod out of your RCBS die
and then run your brass through.
Once you have them sized up, put the pin/rod back in and run
them through again.
Might be worth a try????
Good luck.
Click to expand...



I have a decapping die. I will give your suggestion a try.

Thanks,
Hugh
 
OK, I tried it, and got the same disappointing result as before. I just do not understand why Kamlooky can, with apparently no special methodology, produce a very acceptable result, while I have tried every trick I can think of or has been suggested, and I get case that have deeply dented shoulders every time. ??????

As I said, I use RCBS lube on a lube pad. I also found some old Lyman lube and tried it. I have a feeling that the type of lube or the method of applying may be the answer. I just don't know what else it can be.

Anyone else have any ideas?

Hugh
 
Read my post a couple of entries back!! [Post #12]
Do NOT roll cases on a lube pad....too much lube on the shoulder area.
Remember, the shoulder is going to be moved back when you size that case.
Apply a sparing amount of Imperial sizing wax with your fingers on the body of the case ONLY.
Stay away from the shoulder area.
You may want to clean the lube out of your sizing die and start over.
Perfect shoulders every time!!
Eagleye.
 
To Eagleye you will liisten! Know his stuff does he! Mhmmm hmmmm hmmm hmm...

I SWEAR by Imperial sizing wax, I haven't ever found anything that works so well, with so little.... one tiny little tin lasts a LONG time.. and if I ever lube a neck, I use powdered graphite in the smallest shot I have, in a pill bottle. Just dip it gently in the shot, but stop before you get near the neck, gently tap off the excess.
 
Eagleye said:
I have made a lot of 308 Norma cases from 300 Win Mag.

A couple of tips: Do NOT get any lube on the case where the shoulder is or will be!!
{Imperial sizing wax is the best!!}
This will help eliminate the creases/dents at the shoulder of your new case.

New Winchester brass works best!! But RP is pretty decent.
I don't bother playing with Federal cases, since they tend to be on the "soft" side.

I trim to 2.550" after the sizing is done.
The cases will "grow" slightly on the first firing.

Regards, Eagleye.
Click to expand...

I've been reading through your thread and the posts to it and I have to say, from what case forming I've done, converting 300WM to 308NM, I've never had a problem doing so and my experiences mirror those of Eagleye.

I've used quite a variety of resizing lubes over the years and especially when it comes to some of the more difficult aspects of case forming, there may be some choices that work as good as Imperial but none that I've found to work better.
 
Make sure your little hole buried in the threads of your die hasn't
plugged up either.
I roll my brass on the lube pad with the neck/shoulder area off
the end of the pad and only roll them once.
 
kamlooky said:
Make sure your little hole buried in the threads of your die hasn't
plugged up either.
I roll my brass on the lube pad with the neck/shoulder area off
the end of the pad and only roll them once.
Click to expand...

There is the secret!! Keep the lube of the shoulder area! {this includes the area that will be the new 308 Norma Mag shoulder}
 
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