The Firing Line Forums - View Single Post - How to conv. 30-06 brass to 358Win brass?

Crankylove · July 17, 2009, 02:15 AM

My .358 Win RCBS dies have a tapered expander. Technically, you can do it from 30-06 (also .270, 25-06, 243, etc.) but its much easier to use .308. When Winchester introduced the cartridge, they simply used the .308 necked up to .35 caliber with no other modifications to the case, so starting with .308 brass greatly simplifies things. When I run .308 brass thru my dies, it gets the neck expanded, and your done. No need to trim, no bumping the shoulder back, no extra steps involved. You can also find new Winchester headstamped .358 Win brass fairly easily (at least in my area), if you don't feel like making your own.

If you do end up forming brass from .308, I would use only comercial brass. I have tried using surplus cases, cause I pick them up all over, but some of the case necks have thicker walls than comercial brass, and will require reaming in order to chamber.

July 17, 2009, 02:15 AM	#6
Crankylove Senior Member Join Date: July 8, 2008 Location: 4B ID Posts: 1,770	My .358 Win RCBS dies have a tapered expander. Technically, you can do it from 30-06 (also .270, 25-06, 243, etc.) but its much easier to use .308. When Winchester introduced the cartridge, they simply used the .308 necked up to .35 caliber with no other modifications to the case, so starting with .308 brass greatly simplifies things. When I run .308 brass thru my dies, it gets the neck expanded, and your done. No need to trim, no bumping the shoulder back, no extra steps involved. You can also find new Winchester headstamped .358 Win brass fairly easily (at least in my area), if you don't feel like making your own. If you do end up forming brass from .308, I would use only comercial brass. I have tried using surplus cases, cause I pick them up all over, but some of the case necks have thicker walls than comercial brass, and will require reaming in order to chamber. __________________ The answer to 1984 is 1776 Last edited by Crankylove; July 17, 2009 at 02:24 AM.