Neck tension questions here.

[Peterbilt2007]

When I resize my brass (Lapua) I don't feel the expander touching the necks at all.

This means something. You said that your sized neck ODs are actually 2thou under loaded OD. What size is your expander button?

I do resize the the full length of the neck. At 2.940 much of the bullet is inside the case. Hope that info helps.

It does help, but your OAL is meaningless without knowing what bullet is seated.
Also, you said you're bushing sizing. This is not normally FL sizing of necks, but partial sizing. You should be able to see how far down the necks you're sizing.

Is this new/annealed brass?

I don't have the die in front of me to measure the expander button . Bullet is a 140 gr. Berger .Hybrid. I had the die adjusted to where the bushing was sizing the whole neck of the case. I could see the marks from the bushing. The die allows you to adjust how much of the neck gets sized. Brass was twice fired and not annealed.

 

['Freak]

Is this a factory gun/chamber or custom? Other most helpful information would be: (1) neck outside diameter of fired brass, (2) neck outside diameter with bullet seated, (3) neck outside diameter of sized brass after pulling the neck back over the expander button, (4) remove the expander button and get neck outside diameter of sized brass without expanding, and (5) what neck bushing sizes do you have on hand?

 

[mikecr]

Peterbilt2007, At 2.94 COAL, and 140Hyb, you have bullet bearing seated right through neck/shoulder junction into the case, and you're actually sizing the whole neck(which is sizing donut onto bearing).
With this plan, you're gonna have neck tension problems no matter what you do.

 

[artbosco]

Peterbilt2007 didn't say he was shooting a 6PPC up in a pressure node. He said 6.5x284, which cannot be used at 6PPC pressures.
He also didn't say whether he was jammed or seated off the lands, or if his resulting tension remaining from sizing actually measures 2thou under cal or not.

Chances are that he has a good bit of seated bearing in the necks, probably as much as the bushing is sizing. This would be nice to know.
All these things would have to be known to even begin speculating about pressure difference as a factor(which tension is all about).

The 6PPC and N133 was used ONLY AS AN EXAMPLE!

 

[1shot]

To the original OP, there is a wealth of good knowledge here. When I start with a cartridge that I have no personal knowledge of, I know that in my "tool up" costs it is gonna include 4 different bushings. I, like you are embarking on a new cartridge to me it's the 284 Shehane. Thanks to a fellow forum member that graciously loaned me a reamer, I had a starting point for what to turn my brass to and what to use for a bushing. As I have found with several other overbore cartridges, they seem to like a little more clearance than others to shoot there best. I have also found that the reamer need to cut to allow a good release of the bullet. I have the bbl. chambered and in the action. I'm waiting for shooting weather, (I'm in Ohio) to start my testing. As others have said, change only one variable at a time. If you do, you better be certain of one of the changes or you will be chasing your tail.
I hope this helps,
Lloyd