Setting up 358 full length die

[Carphunter]

I've been sizing 308 and 358 brass with a full length die for a while now.   I'm trying to refine my setup, though, so I work the brass as little as possible.

Problem is... between 308 brass being resized, and 358 native brass sized in the die... I get two different headspace measurements.  argument's sake... 308 brass comes out of the die with a 1.625 HS, and the 358 comes out at 1.619.  (for my gun...perfect world I want the brass at 1.624")  starting case lengths are the same (2.005)

My best guess is that the expander ball on the redding die is "pulling" the neck and shoulder when it comes out of the 308 brass a little more than the 358 (or the 358 brass isn't as affected by the process).

Short of finding a neck die (I haven't found one yet, and I'm out of positions on my turret anyway), how would you attempt to get the two types of brass coming out of the die at as close to the same size as possible?  Or...can it not be done?  Or do I have to suck up....size all the 308 to358, load and fire it, and then reset the die to load all the converted 308 once fires, and the 358 fired brass?

[Gun 4 Fun]

That is exactly what I would do if I were going to all that trouble, but unless you are using it for bench rest or something, why bother? It won't make any difference in the field, and I seriously doubt that you will be able to see any difference at the range as far as groups sizes go. It is just one of the things that you have to deal with when forming cases from one caliber to another. I have done it for 25-06 from 30-06, 35 Whelen from 30-06, etc. I haven't ever seen any difference in groups, or case life for that matter. I just resize them, load them with slightly below max loads and fire them. Then I set my die to size down to just off/above the neck/shoulder junction.

[stimpylu32]

I've been sizing 308 and 358 brass with a full length die for a while now.   I'm trying to refine my setup, though, so I work the brass as little as possible.

Problem is... between 308 brass being resized, and 358 native brass sized in the die... I get two different headspace measurements.  argument's sake... 308 brass comes out of the die with a 1.625 HS, and the 358 comes out at 1.619.  (for my gun...perfect world I want the brass at 1.624")  starting case lengths are the same (2.005)

My best guess is that the expander ball on the redding die is "pulling" the neck and shoulder when it comes out of the 308 brass a little more than the 358 (or the 358 brass isn't as affected by the process).

Short of finding a neck die (I haven't found one yet, and I'm out of positions on my turret anyway), how would you attempt to get the two types of brass coming out of the die at as close to the same size as possible?  Or...can it not be done?  Or do I have to suck up....size all the 308 to358, load and fire it, and then reset the die to load all the converted 308 once fires, and the 358 fired brass?

Fireforming is about all you can do at this point    with a .005 diffrence between the factory and formed cases I'd just load and shoot the 308 cases  , once your done with that they should match your fired 358 brass except for length , at that point trim them all the same an load away . 

stimpy

[rickt300]

My last 358 was a Browning BLR and I had misfires with factory 358 Winchester cases but reloads made from 308 cases worked perfectly.  You need to lube the inside of your case necks with Armorall Protectant. Though not made for the necking up of cases it acts as a miracle lubricant and you don't even have to remove it.  I wrap a strip of the Protectant "Wipes" around an old smaller diameter copper cleaning brush and wipe the inside of the case neck with it.  Reduces friction incredibly.  I do this in every instance where I am having dificulty gettin my expander ball thru the neck.

[Carphunter]

I ended up just lubing with imperial more than i normally do...making sure to get down under the neck to the joint with the shoulder.

I'm firing up around 80 of these sized rounds... that makes the brass take the volume my 358 native shells have.

I then will test to see if the newly sized 308 and 358 brass then responds to the die/ball the same way.

[sgtt]

A Lyman M die might work prior to FL sizing. 

[Carphunter]

after sizing my 308's to 358, i loaded and fired them with a 200 hdy spire pt and 48 gr.  when I size them now, they and the native 358 brass respond almost identically in the die... so I'm good to go.