Another neck turning question...

[gjb89]

I am using a PMA tool for turning once fired Hornady 6.5 creedmoor brass that was resized with a non-bushing die, then chamfered and trimmed with a Giraud trimmer and then expanded with the mandrel. My rifle does not require a turned neck to chamber I am just seeking a more consistent neck tension, so I am trying to turn roughly 75% of the neck. I am getting a ring around the neck of the brass that is not getting turned (see picture attached of multiple views of one piece of brass). Here are the measurements I am getting prior to turning.
closest to opening of the cartridge :.01125 wall thickness and .2865 O.D.
closest to shoulder junction :.01225 wall thickness and .2885 O.D.

What am I doing wrong? Pictures I see of turned brass seems to be only turned on one side. Thank you in advance.

 

[Uncle Ed]

Your neck turning tool is removing the thicker high spots on the neck and you are doing nothing wrong.

If you had a Redding neck thickness gauge like below the thicker "high spots" are clearly indicated vs individual readings using a micrometer. I also notice almost all my cases the neck will get thicker closer to the shoulder like yours.

I also like the how the angle on your cutter matches your case shoulder angle, nice job. The only check I would make on your necks is measure the difference in what was removed and untouched on the neck with a ball mic.

Last night I was neck turning some Lake City 7.62 brass and my neck turner was set to only remove .015 or more neck thickness, And my cases looked just like yours, and to turn 100% of the neck the neck turner would have to be set at .014.

When neck turning I believe "less is more" and try to keep the neck thickness variations within .001 plus or minus. And I only do this to keep the neck runout at .001 or less after sizing.

I only neck turn because I'm retired and have noting to do and all day to do it. And neck turning beats reading posting with F. Guffey in them and his magic feeler gauges. (WARNING neck turning and reading F.Guffey postings can be stressful and cause headaches)

 

[Jeff A]

I have the PMA tool and for what you are doing, it looks OK to me.

 

[243winxb]

6.5 SAAMI chamber neck is tapered. .296" at the case mouth and .297" at the shoulder.

Could brass spring back cause? --

closest to opening of the cartridge :.01125 wall thickness and .2865 O.D.
closest to shoulder junction :.01225 wall thickness and .2885 OD

I see no reason to turn only 75% of my 243 necks. They get a full cut. Factory chamber.

 

[gjb89]

Awesome thank you for the replies!

 

[243winxb]

This mixed lots of LC brass may look like only 75% is turned, but the cutter skimmed it, leaving the original brass color.

My old Lyman discontinued outside turner does ok for my usage.