When to turn

[heikki02003]

Just wondering when you turn necks. I have brand new .284win WW brass and I'm going to neck turn just to clean them up,approx 80%). Do you turn necks before fireforming or after? Why? I like to trim to length after fireforming because the brass undergoes some serious stress and stretch that first fireforming shot. But what about neck turning?
My thinking would be to turn them after. I'm thinking I will:
1. Fireform
2. FL size
3. Trim to length
4. Run them through an expander mandrel
5. Turn necks

But I could:
1. Run them through an expander mandrel
2. Turn necks
3. Fireform
4. FL size
5. Trim to length

Any comments or opinions?
Thanks

 

[Eddie Harren]

Depends on your neck diameter. If you have a "tightneck" chamber, then you'll have to turn before fireforming. If you have a SAAMI chamber then you can do it before or after.

 

[Preacher]

Are you sure you'll need to turn your necks ?
If it's not a tight necked chamber you may be creating a problem with longevity of the brass by increasing the clearance, and then squeezing them back down time after time...

 

[heikki02003]

Thanks guys for the concern. I very much understand when to turn and when not to. For this rifle I am turning necks.
I'm building a relatively tight neck .284. My loaded WW brass measure .314 to .316 before turning. My reamer from Dave cuts a .317 neck. I am going to turn the brass to .314 for a .003 total clearance neck. I've read, and Dave at PTG suggested the .284 needs considerable neck/chamber clearance, or guys are getting inconcistant release. I'll start with .003 and see how it shoots, if I'm not happy I'll take off another .001 to give me .002 per side, or .004 total.

I've kind of answered my own question. I was just hoping I wasn't missing something about my order. I am going to turn them before fireforming. One thing is right now they have nice clean necks that will ensure I get a good fit on the turning mandrel.
I know the benchrest guys turn necks twice. Once to simply have them fit in their chambers, then they fireform, then they trim again for final finish. My original questions was designed to maybe get some discussion around this idea, kind of the pro's and con's of turning before or after fireforming. I think that the two step turn process would help with concentricity and uniformity.

 

[Preacher]

Generally it's better to turn once and then return the necks again after firing once to make sure everything is where it belongs ..
The only time I turn before firing is if it's needed to chamber, otherwise it's always after...... and then again for a check....