How-To: Convert .30-06 Brass to 8x57 Mauser?

[Jayhawk Dan]

Little help here please! I want to convert .30-06 brass to form 8x57 Mauser brass, and I need some specific directions--a recipe?--on how to do this. Would someone please give me the directions to do this or direct me to a source for this information? I am an experienced reloader/handloader, but I have never necked up and fire formed brass. Thanks in advance for your help!

Jayhawk Dan

 

[john wall]

The case neck will be a little thick on this conversion, and pressures may be excessive. Pony up and buy PRVI 8X57 brass from Graf & Sons. 100 new cases doesn't cost that much.

PRVI also makes good hunting bullets. Considering its fast twist, the Eight does better with heavier bullets (no less than 170 gr, no more than 200) at a moderate velocity. 8mm Remington Magnum bullets will not work well on game at the speed the Eight will push them.

The Nosler 200 gr Partition will anchor ANYTHING in North America if loaded to 8X57S pressure levels.

With that said, my Sporting Eight does very accurate with the Hornady 150 gr Spire Point.

European 8X57S ammo is loaded to 61,400 PSI. Higher than 308 or 30/06.

If you are going to shoot heavy hunting loads use the right brass.

BTW, my 1948 Husqvarna Sporting Rifle in 8X57S is my favorite rifle in my all-time favorite caliber.

I highly recommend the Redding Competition Shellholder set so proper headspace may be maintained on your brass. Many European rifles have "generous" chambers.

 

[medalguy]

You can always ream the neck if it's too thick.

To convert the brass, RCBS makes a set of dies that will resize the brass and allow you to file trim the brass to the correct length. Just be sure you watch your loaded brass. It can be very confusing to have ammunition marked .30-06 on the head but really chambered for 8mm. The two rounds look very similar. Don't confuse them.

 

[ReloaderFred]

All I ever did to convert .30-06 to 7.92X57 is run them into the 8X57 sizing die and then trim them to the proper length. Then I loaded them with about 15 grains of Red Dot and filled the case with corn meal, lightly tamping the corn meal in the mouth of the case to keep it in place. Then I fired them into the air to fire form the cases to my chamber.

Don't do the fire forming in your garage, since it's loud. There is also a lot of pressure being produced, so use the same safety precautions you would use with live ammunition. You'll also want to swab the bore and chamber every couple of rounds to make sure none of the corn meal gets in the chamber and dimples your cases.

There will be a ring around the neck of your reformed cases where the shoulder of the .30-06 transitioned into the neck. I never found this to be a problem with the converted cases. Now I just use proper 7.92x57 brass, since it's more available than it was when I had to resort to forming my own about 25 years ago.

In my K98 and V24 rifles, I always got good accuracy with 150 grain bullets, using IMR 4895 powder.

Hope this helps.

Fred

 

[john wall]

Obviously, one can buy a reamer, and go through a lot of drama to do this conversion.

It would be cheaper to buy 100 new cases than to buy all the other stuff required, and still need to fire form brass.

Been there, done that decades ago, and it simply is not worth the trouble.

BTW, a reamer and forming die is over $50. 100 rds new PRVI brass is under $50.

You do the math.

 

[TonyT]

I did a lot of brass caliber conversion in days bygone forming 8x68S, 40-40 PWC, 40-50 SS etc. Today with the availability of brass and the higher cost of forming dies I would not bother with case forming and opt to purchase the brass.

 

[R.W.Dale]

Chances are with a Mauser chamber the neck will not be too thick.

Being military cartridges first I've not seen a Mauser chamber yet that didn't offer ample clearance for a grossly over thickness neck.

I've made 7x57 from 30/06 and even for a commercial chamber I still had several thousands of clearance. Checking a loaded formed case against a fired in the rifle case is all that's needed to verify.

So basically my procedure was size,trim, load and rejoice

 

[gpb]

I purchased a Yugo M48 several years ago. For some reason I couldn't locate any 8X57 brass. I had some .30-06, so I formed some 8X57. I followed the same procedure as R.W.Dale did in post #7.

I also was worried about the thicker neck, but since the chamber was a little oversize, as is common with military chambers it was not a negative. The brass worked fine. It doesn't hurt to verify the neck dimensions, but they usally are not a problem on this particular re-form.

If I can find good 8X57 brass I don't waste my time with the reform. I only resort to this if I can't find 8X57. It's just nice to know that I can do it if needed.

 

[Clark]

I have used 8x57 brass in 257 Roberts.. that always works.
I have used 308 brass in 260Rem..... that works 90% of the time.
I have used 308 brass in 243..... that is always a bad idea.

These days I like to measure the chamber neck with pin gauges and measure the cartridge neck with dial calipers. I like to know how much clearance I have.

This year i will do outside neck turning of Lapua 308 small primer brass so I can run higher pressures in 243 and 260. I have the Forster outside neck turner adapter set up in the drill press with a system for the two shafts to align.

 

[ranger335v]

Modest reforming is quite easy for most of us and your conversion requires no special die, etc. Do as Mr. Dale suggests and all will be well.

I believe a Dremel tool with a thin 'cut-off' blade works very well to eliminate most of the excess case neck, use a case trimmer to complete the job.

 

[Bigdog57]

During the 2008 election cycle, brass got very hard to find in all common calibers. I was greatly ramping up my reloading, and we had a Sportsman's Warehouse store locally (now closed). 8X57 brass was nowhere to be found - and I had two coffee cans of .30-06 with no rifle to match.
So, I reformed it and loaded them - they shoot fine. Had a bunch of bad Turk and Yugo 8X57 ammo (no fires), and pulled their bullets and loaded for the specific weights. 8X57 bullets have gotten darned spendy!
I also formed .243Win into .308Win, .204Win into 7.5 Swiss. No problems with any of them. I was desperate for the .308Win, and actually bought a couple bags of new .243 for that project! One uses what's available.
Nowadays I order online, when I find the proper brass in stock. But having the knowledge to reform it can come in handy!

 

[gpb]

As I stated in post #8, I have formed 8X57 from 30-06. One note of caution is to make sure that your loads are clearly marked. Remember that you now have a 8X57 with a 30-06 head stamp. Be very careful not to accidently fire an 8X57 in a 30-06. That is not a good combination.

 

[280shooter]

I did the same thing this past fall. I used my dremal to cut them first. then i used my reg. 8mm reloading die with the decaper removed.Then I just used my trimmer to trim the rough edges off. Deburbed in and out and reloaded..
works for me.I dont have a 30-06 anymore. so no worry in making a mistake in loading 8mm n a 30-06. But if you have both,, I would paint the bottom of the case,

 

[fguffey]

Thicker neck? I have formed 8mm57 cases from everything 30/06, then there are those that do not measure before and again after and do not do research, the 8mm57 chamber has a generous? neck. Reminds me of a ‘few’ friends, they wanted 280 Remington rifles, they had a 280 Remington reamer, and that is all that was required to chamber a 7mm57 to 280 Remington, they thought.

After a trip to the range they discovered the ‘generous’ neck diameter of the 7mm57, the new creation (280 Remington) had two different neck diameters, seems the 280 Remington reamer did not clean up all of the old chamber. Other friends wanted 30/06 chambers, they had the reamer and a rifle chambered in 308 Winchester, again, the 30/06 reamer did not clean up the old 308 W chamber.

I am putting a couple of bench rest type rifles together, and I was told “All you gotta do is.....”, then I ask to see the fired cases and of course no one has fired cases, seems all the experience comes from the Internet in the form of memory work.

Forming 8mm57 from 30/06:

http://www.midwayusa.com/product/77...57mm-mauser-8mm-mauser-from-30-06-springfield

OR

http://www.natchezss.com/product.cfm?contentID=productDetail&prodID=RC15565

Forming with a forming die requires the ‘man tool’ the hack saw, and the file, I have hundreds of air craft counter sinks, I do not recommend them to a reloader.

After forming and trimming it is necessary to full length size to minimum length unless the person going the forming understands it is possible to place the shoulder exactly where they want they want it, meaning when forming a case like the 8mm57 from 30/06 the length of the 8mm57 from the head of the case to its shoulder can off set the length of the chamber if the person knows ‘the length of the chamber from the bolt face to the shoulder of the chamber’, If the reloader is a case former there is no excuse for not knowing the length of the chamber. The shoulder of the 30/06 is erased and becomes part of the shoulder and neck, the shoulder of the 8mm57 is formed .121 thousandths further back than the shoulder of the 30/06, the reloader that is a case former can and should be able to off set the difference in length between the chamber and and case, or they can mindlessly pull the handle, raise the ram and full length sized the case, then go to the range and fire form.

As to choices, again, the best investment is the 308 Winchester trim/form die, I do not recommend the 308 W trim/form die to reloaders for anything but forming 308 W cases.

F. Guffey

 

[fguffey]

“so no worry in making a mistake in loading 8mm in a 30-06. But if you have both,, I would paint the bottom of the case”

A fired many times 30/06 is a bad choice, as to painting a case head, I have purchases thousands of new/unfired pull down cases from Pat’s, for .08 cents to .11 cents each, new/unfired is the best choice, military is a better choice over commercial 30/06, the military case does not have a chamber designation, chambering an 8mm57 in a 30/06 chamber is some scary stuff. Still, it requires effort to close the bolt, is is not smart to ignore/disregard warning signs.

F. Guffey

 

[Jayhawk Dan]

Thank you!

Thanks to everyone who replied to my question on this topic! It was good of you to offer your knowledge, experience, advice, and suggestions; all have been very helpful to me.

I think that as of right now I have enough information to proceed. If I run into unforeseen problems, I'll be back to this forum with more questions. The THR is one of the best forums I use. Thanks again!

Jayhawk Dan