Neck-Turning Advice Sought

[South Pender]

I've just turned the necks of some virgin cases. I did this by first running the cases over an expander mandrel to open them up by an additional .001" over the usual .002" under bullet diameter. In other words, these 222 Rem. cases have an ID of .223, rather than the .222 usually produced by full-length sizing the cases. My question is: Should I now run the cases through my FL die to get the ID back to .222 in order to have sufficient neck tension on the seated bullets? Once fire-formed I plan to neck-size only using a Wilson chamber-type die with the right bushing.

Any suggestions?

 

[LHSmith]

If the expanding mandrel is of the same make as the neck turning mandrel you should be good to go. I strongly advise against neck sizing. FLS every time if you want consistent accuracy. You don't mention your chamber neck diameter. If a factory chamber, i would only cut the necks to get the high spots.

 

[SG4247]

I have a similar question.

On fired brass, I have to FLS with a neck bushing because the turning mandrel falls through the as fired brass.

So, FLS first with a neck bushing smaller than the mandrel, then expanding using the proper turning mandrel so it fits perfectly, then turn to desired wall thickness, then neck size again with a smaller bushing to pass the pin gauge for neck ID check, and so neck tension is consistent.

What a PITA.

Now, this process has worked very well for accuracy, unless the runout gets bad on the neck, in which that case gets culled out.

Is there a better way?

 

[South Pender]

I strongly advise against neck sizing. FLS every time if you want consistent accuracy.

I'm surprised by this advice. Wouldn't you do better accuracy-wise by sizing only part of the neck (the way that the Wilson die does this), so that the chamber-size case body and 1/8" of the neck better center the loaded round relative to the barrel? With FL-sizing, the loaded round will always lie on the bottom of the chamber meaning that it isn't optimally centered relative to the bore.

 

[LHSmith]

^^^^^ Virtually all Benchrest competitors full length size their cases, have been doing that the last 20+ years. Google : riflemansjournal.blogspot.com/2010/06basics.resizing for an explanation as to why.

 

[LHSmith]

I have a similar question.

On fired brass, I have to FLS with a neck bushing because the turning mandrel falls through the as fired brass.

So, FLS first with a neck bushing smaller than the mandrel, then expanding using the proper turning mandrel so it fits perfectly, then turn to desired wall thickness, then neck size again with a smaller bushing to pass the pin gauge for neck ID check, and so neck tension is consistent.

What a PITA.

Now, this process has worked very well for accuracy, unless the runout gets bad on the neck, in which that case gets culled out.

Is there a better way?

Turn unfired brass only. Too many variables introduced once brass has been fired.....1/ not all cases work harden at the same rate- - springback will vary case to case = inconsistent neck walls 2/ you have to contend with the layer of carbon in the necks

 

[jr600yd]

If you have a tight necked chamber you must turn the necks. If not I wouldn't do anything to the necks until the brass has been fired at least once.

A lot has been mentioned over time about "accuracy" of turned or not brass. Bench rest guys do it all the time, then again they usually run tight necked chambers. If you have a standard chamber you probably won't see any change.

The advantage to turning necks for a standard chamber is increased case life. Not working the brass as much.

 

[South Pender]

Just to clarify what I wrote in the opening post, I didn't size the virgin brass. I just ran the expanding mandrel through all the new cases. Then I turned them. The rifle (a Cooper M21) has a standard chamber; I haven't made a cast to measure it.

 

[Deleted old_dood]

I've just turned the necks of some virgin cases. I did this by first running the cases over an expander mandrel to open them up by an additional .001" over the usual .002" under bullet diameter. In other words, these 222 Rem. cases have an ID of .223, rather than the .222 usually produced by full-length sizing the cases. My question is: Should I now run the cases through my FL die to get the ID back to .222 in order to have sufficient neck tension on the seated bullets? Once fire-formed I plan to neck-size only using a Wilson chamber-type die with the right bushing.

Any suggestions?

I'd resize the neck after turning otherwise you're not getting the neck tension that you just sized for.

 

[MQ1]

^^^^^ Virtually all Benchrest competitors full length size their cases, have been doing that the last 20+ years. Google : riflemansjournal.blogspot.com/2010/06basics.resizing for an explanation as to why.

I read through this, and German specifically states that full length resizing is how highpower shooters tend to roll. What about full length sizing with a neck bushing, is that any different?


MQ1

 

[Dusty Stevens]

Yes benchrest shooters use a FL bushing die

 

[spclark]

What about full length sizing with a neck bushing, is that any different?

In principle, none at all. In practice using bushings allows some control over neck tension.

The biggest hurdle is determining which brand of off-the-shelf die system works for your rifle(s) under your condition(s).

Sometimes none will work as good as a custom die set made specifically for your use but of course there's an advantage price-wise to using something ready-made.

 

[amlevin]

^^^^^ Virtually all Benchrest competitors full length size their cases, have been doing that the last 20+ years. Google : riflemansjournal.blogspot.com/2010/06basics.resizing for an explanation as to why.

Agreed on the FL sizing but most only do that AFTER they have neck turned the virgin brass.

Even the so called "best" brass has it's case neck (and case wall) thickness variations. It's just not as much as he cheaper stuff. Yesterday I just put another 100 pieces of Lapua .223 Match brass in service after carefully measuring and turning the necks. The best cases were exactly .013" Some were .0006 more and some .0005 under, in varying points on on the neck circumference. After turning, using a nice snug mandrel, the finished cases were all .013" +/- .0002".

NOW I will F/L size after every firing, knowing that I first won't push the eccentricity of the neck IN, only to be followed by pushing it back OUT with an expander mandrel.

When I follow this procedure I get seated bullets that are nice and concentric, load after load.

FWIW, I don't think my method is unique.