30-.338 Winchester Magnum Reloading

[Gone Ballistic]

I acquired a 30-.338 WinMag some time ago in a trade that has been in my safe ever since. During this time of self imposed lockdown I thought I would try to make some brass for it and reload some of it.
Have any of you done resizing of this or other large caliber rifles? I received some RCBS FL dies with it but upon trying to resize some cases I noticed some case side and neck collapsing. I am sure I will also have to turn the necks down but am wondering to what wall thickness?
Any help or ideas will be appreciated as the only cases I have reformed in my years were 25-06 from 30-06 and. 270 Winchester. This was over 50 years ago.
Thanks!

 

[L.Sherm]

You can neck down 338WM brass to 30 cal or I believe just buy it from Grafs.
As far as turning necks its gonna be a guess untill you have a fired case to compare with a loaded round or look at a print that was used to chamber it. You could do a chamber cast if all else fails to figure out your neck dia in your chamber.

 

[L.Sherm]

Trying to neck down to 30 cal with the dies you have maybe trying to do it in to big a step, a bushing die guys use to do it in 2 steps. May be better of to just buy the brass.

 

[degreen]

I have a 30-338 win mag. I use 338 win and 7mm rem cases. I would try forming, then fire forming 7mm rem case to see how much room you have in your chamber for your neck. Check your expander ball on your full length sizer die. I found mine not to have enough taper to neck up 7mm rem mag brass. I am getting 3100 fps with 180 SGK's and 67 grains of IMR4350 out of a 26" barrel.

 

[Len Backus]

Moved to RELOADING.

 

[Jerry M]

In addition to 7mm Rem Mag cases mentioned above, you can also use .300 Win Mag cases, but they will need to be trimmed.

 

[degreen]

In addition to 7mm Rem Mag cases mentioned above, you can also use .300 Win Mag cases, but they will need to be trimmed.

I have tried 300 win cases numerous times, and always crushed the shoulder.

 

[Edd]

Are you using new brass? I don't think you should be having any issue with new 338 brass. Used brass could have some depending on it's condition.

 

[TOM H]

I have 2-30-338mag. One I neck down 338 mag case other use 7mag case. I have RCBS trim/form dies for 30-338mag and I use that for 338mag case.

If can't find one might try here. http://www.ch4d.com/products/dies

Sierra # 5 has loading data for 30-338mag

 

[fguffey]

I form 30/338 out of almost anything with a belt. A friend needed 400+ 8MM338 MAG, he called me, had he been able to form the cases he would have never involved me. First I had to determine what was required, I have 16 forming dies, short forming are my favorite.

F. Guffey

 

[Plinker147]

I preferred 338 WM neck down and trimmed. I did some 7mm rm necked up, they will be short when you do. A couple of firings and they stretch to size.

You can use the OLD 308 Norma mag (not the new) reloading info, as case is very similar if not the same. My load was 71gr IMR 4831 with 180 BT at around 3000fps

 

[JMW67]

I acquired a 30-.338 WinMag some time ago in a trade that has been in my safe ever since. During this time of self imposed lockdown I thought I would try to make some brass for it and reload some of it.
Have any of you done resizing of this or other large caliber rifles? I received some RCBS FL dies with it but upon trying to resize some cases I noticed some case side and neck collapsing. I am sure I will also have to turn the necks down but am wondering to what wall thickness?
Any help or ideas will be appreciated as the only cases I have reformed in my years were 25-06 from 30-06 and. 270 Winchester. This was over 50 years ago.
Thanks!

This has been my go to 30 cal. magnum for years my load is 338 win necked down and turned 73.5gr. h-4831sc cci mag primer and a 168 nosler bt tremendous round you should really enjoy this rifle

 

[Wrenches]

I have necked down many 338 cases and can't recall ever crushing the shoulder. I use Redding dies.
I load 180 grain Sierra's in front of 74.5 grains RL-22 and a 215 Federal primer. Never check the velocity though.

 

[montana west]

the 30/338 is a great round the same a 308 norma magnum.. loading data will be the same. there is a very minor difference in the sholder angle but this is very minor. Because you headspace on the belt -minor is nothing.. once fired the case will be correct and there will be no pressure problems at all. good news 338 cases are better and cheaper than Norma. set you die up a bit and don;t completly resize it just about 2/3 then next step a little more until it will chamber then fireform. it will work out just do it in steps.. remember this is the very best of the 30 cal magnums just like the 300 win. nothing better. those who claim just read magazines and believe all the gun writers bull .