Case forming process 308 to 7mm-08

[CCWdownrangeP2]

I'm thinking of my next rifle purchase and am considering getting a 7mm-08. All firearm purchases by me always take into consideration reloading for that caliber. I've never tried reforming cases from one caliber to another. 308 cases are much more available than 7mm-08 so I would be looking at reforming the 308's. My understanding with the transition of a 308 case to 7mm-08 is that it may be as simple as FL resizing the 308 brass with a 7mm-08 die. Could there be more to it then that? If so, what?
Thanks ahead of time, CCW

 

[ironworkerwill]

It is very do-able by simply FL sizing the 308 brass with the 7-08 die.

Annealing is not necessary but will help.

Your brass will be have a shorter slightly thicker neck. The short neck wont hurt a thing. But, IF the neck is too thick it will need to be turned or reamed. Turning is better IMO.

 

[fguffey]

Your brass will be have a shorter slightly thicker neck.

Help me, how does the neck get shorter and thicker? Or, what makes it shorter? and or what cases the neck to get thicker?

F. Guffey

 

[ironworkerwill]

Common sense tells me it would be longer and keep its original thickness. I turned 100rds of Hornady Match 308 into 7-08 and every single one was shorter and thicker. It didn't matter if it was annealed or not. ????

 

[CCWdownrangeP2]

What entails the turning or reaming process?

 

[ironworkerwill]

http://www.brownells.com/userdocs/products/p_749012890_6.jpg It shaves off the out side of the brass if the brass is too thick. You may not need it.

 

[Jim Watson]

Did you have to neck turn? Most commercial chambers are sloppy enough that they would benefit from a little thicker neck.

 

[ironworkerwill]

I had to turn mine for a custom barrel. The Ruger M77 worked fine.

 

[CCWdownrangeP2]

Thank you all for responding. I didn't think this would be very complicated. My new rifle will be a commercial model, not custom, so I don't perceive very many problems. Now to continue my research as to what rifle to buy.

 

[GooseGestapo]

Two things;
1. It's easier if you size the .308 in a .308 die first. Then run through the 7mm die. Done this about a thousand times and never ruined a case.

2. It's necessary to run a once-fired .308 die into either a .308 sizer or a 7mm08 sizer before necking down to .260.
I had about 15% shoulder collapses trying to directly size .308 to .260... Ditto, .308 to .243.

fwiw; all my .260 brass is .243 necked up to .260. Very, very simple. Just like reloading .243 with "different" bullet.

also, best 7mm08 brass I have is some PMC that I got as factory loaded ammo. From 20" bbl, the factory ammo gives 2,900+fps and occasionally one will trip the chrono' at over 3,000fps. Upon reloading the brass the first time, I found that sized brass would chamber but loaded with bullet, wouldn't !!! I had to neck turn with Forster Hand-neck turner to get brass to "work". However, with Sierra 140gr GameKing over 46.5gr of IMR4350 (and now 47.0gr of RL17 for ~2,900fps) I get best accuracy rifle is capable of.
btw; rifle also has a very "tight" neck and throat... Suprising on a factory Rem. Mod-7...

 

[Louca]

I also have a 7mm-08 and in my younger days I used to process .308 brass into 7mm-08. But if I was doing it today, I would just buy some 7mm-08 brass and reload that. Otherwise, you will need to get into the trimming reaming process to make them right. Also, when you are done, the cartridges will have the correct stamp on the bottom.

If you enjoy the process of re-forming the brass, go for it. After the first firing, the brass will form to your chamber and after subsequent firings the cases will lengthen, too. I didn't have a .308 sizing die, so I did lose some cases to case collapse/denting.

Lou

 

[ironworkerwill]

Goose Gestapo, did you notice that the necks were also shorter after necking down?

Yea, it is much easier to size up from 260 to 7-08.

Also PPU makes really good budget 7-08 brass. Norma brass is the best I've used so far. I've heard lapua 260 is better still.

 

[Reloadron]

This question comes up from time to time. Years ago I chambered a M1 Garand in 7mm-08 Remington and before I had any 7-08 brass I simply took new factory 308 Winchester brass and ran it through 7-08 dies. Any changes in neck thickness did not require neck turning or reaming, they chambered and shot just fine. They hand loaded just fine. Maybe a year or two ago there was a thread on doing this and I ran a few and took before and after case dimension measurements but haven't a clue what I did with that data. A forum search may find some of the old threads. Anyway, all that was needed to do was run the 308 brass through the 7-08 sizing process.

If I were to do it again today using once fired 308 brass I might run the stuff through a 308 die first but I doubt it. Run your brass through a 7-08 die and see if it fits. If you are curious measure the neck thickness before and after to see what you get but I doubt any difference will matter.

Ron

 

[grubbylabs]

I have been turning 308 and 7mm-08 into .243 brass without any issues. I just recently got my first .243 and before your know it, it turned into two of them. I don't remember getting the first one wet....

The only thing I have noticed is that they turn out shorter. I did not do any sizing prior to running through the .243 die, just tried it out on some scrap brass in my scrap bucket. It worked quite well. So I dug through my scrap bucket for all the 7mm-08 brass I could find, then I tried a scrap piece of 308 with a bad primer pocket, it also chambered just fine. So I took a few 308 that were good and ran them through to complete my box of 50 so I could do my load development.

 

[GLOOB]

I have no problem with chambering converted brass in my rifle. But the thicker neck caused problems to my expander. The expander ball wanted to stick and stretch and cause me a horrendous, teeth-chattering workout, no matter if I lubed up each case neck. And I wouldn't want to have to lube up each case neck, even if it worked. So when someone pipes up with "Imperial!" thanks, but no thanks.

If I had a trimming system where I could add a neck turning system, I might have gone that route. But I happened to discover the Lyman M die. It solved that problem and many more.

I much prefer to convert .243 to 7mm08. Of course .243 cases aren't nearly as available.

 

[kwg020]

Just from my experience turning 308 into .243:

Anneal first
Use a 7-08 trim die to start the conversion
Finish with the 7-08 FLS die
(I do this one more time using the .243 trim die and the .243 FLS die)
Put the trim die back in the press and use it to file off any brass that comes out of the top of the trim die. This will also help you find the right over all length of the case.

308 and 7.62 brass is getting cheaper all the time but you need the right tools if you want to convert it to something else.

Just my process. I have not had any issues with thick necks doing it this way but I have not measured brass thickness on the finished cases.

kwg