Turning 308 into 7mm-08, whats it take?

[victor3ranger]

Can't seem to find any once fired 7mm-08 brass for a friend of mine so he wants to know what it takes to tunr the 308 brass into 7mm-08??

Can I just run the 308 brass thru the 7mm-08 resizing die then trim or is there a lot more to this?

 

[criticalbass]

Good strong press, adequate lube and some muscle. Check case length and neck thickness. Much better idea to order brass, but it can be done.

 

[MoBoost]

It's better to turn 243 into 7mm-08.

 

[tyromeo55]

I've done 308 into 243. I'd assume 308 to 7mm-08 would be just as easy.

Take the expander ball out and run the 308 brass into the 7-08 die in short smoth stokes using a VERY thin coating of good lube like imperial. Then trim and anneal if you like.

The brass might need to be fired once in your gun to be fully formed but that is okay

 

[7stw]

If you go this route and you are using 7.62 NATO or mil spec brass you are going to have problems as the necks are thicker than .308 win brass and if successful you are going to experience higher pressure and decreased case capacity. I would look for .243 brass as boost stated or just buy some new brass. Natchez and midsouth shooters showed some Remington in stock over the weekend. I myself unless its a wild cat or scarce shy away from forming cases. And if you do label and keep it separate. Use adequate lube like imperial sizing wax or hornadys one shot lube.

 

[swampratt]

I will third the imperial wax
It is all i use..i have taken 270 down to .308.Had to anneal 2x and turn the necks down..
My .243 has a tight neck area..the ID of the fired R-P cases measure .244" sometimes i have one that measures .245"
Super accurate...
Now my .308 the ID after firing will measure .310"-.314" depending on which brass i use..the tighter will always be the most accurate in my rifle....

SO if you do use 308 and it fits the chamber..do some measuring...it may surprise you as to how things work and or don't work..
There is some accuracy to be had.
If you ever make it to yukon i have 8 once fired 7mm-08 you can have and 5 that were necked up and shot once in a 308

I have used 338 federal in my .308 and i just lube with imperial and size through my lee full length sizer like i would any 308 round...

 

[victor3ranger]

Great info guys, thanks.
He would buy new if he could find it for prices before the crazyness happened but all he has found is stuff for around $1 per piece of brass which is to damn high for something like 7mm-08.
So, just so I make sure I have the directions correct, I should remove the expander ball from the die then slowly run it thru the FL die then when finished see how the brass chambers? Should I put the expander back in and run the brass thru one more time??

 

[Swine]

You necked down 338 Federal

You know how hard it is to find that brass, even new. Seems like federal only gets maybe one shipment a year of that out on the shelves.

 

[Blitzfike]

I did several 308 to 7mm-08 conversions when I got my first 7mm-08 rifle. I did both commercial and military brass. MoBoost is sure right in that the case capacity and wall thickness is greater on the military stuff. I have the Forster neck turning and reaming tools for doing that sort of thing, so other than some work it isn't bad to do. You should adjust the load downward as well if you use the military brass. I didn't have to do anything to the neck with the commercial brass. Don't anneal until after you neck them down. I tried it both ways and had several failures annealing before I ran them into the sizing die. Pushed the neck down into the shoulder. Doing it before annealing worked much better. I am currently shooting 7mm-08 in a single shot rifle, but plan to build a bolt gun for it in the next few months. Hope this helps some.. Blitzfike

 

[Huckelberry75]

I did several 308 to 7mm-08 conversions when I got my first 7mm-08 rifle. I did both commercial and military brass. MoBoost is sure right in that the case capacity and wall thickness is greater on the military stuff. I have the Forster neck turning and reaming tools for doing that sort of thing, so other than some work it isn't bad to do. You should adjust the load downward as well if you use the military brass. I didn't have to do anything to the neck with the commercial brass. Don't anneal until after you neck them down. I tried it both ways and had several failures annealing before I ran them into the sizing die. Pushed the neck down into the shoulder. Doing it before annealing worked much better. I am currently shooting 7mm-08 in a single shot rifle, but plan to build a bolt gun for it in the next few months. Hope this helps some.. Blitzfike

When is comes to tinkering, this guy would know. Ask him about his home made 22 cal bullets...