Tight Throat?

[Bart B.]

Remember, if you're neck sizing via bushing without first 'truing' thickness, all you're really doing is pushing any eccentricity (high spots) to the ID. Then, when you seat a bullet, that eccentricity again is pushed back to the OD, which isn't doing much to build straight ammo...

It doesn't matter if the outside of the case neck is a bit eccentric. That part of the case is not used to center the case neck nor bullet on the bore axis.

Sierra's cases used to test their bullets are that way. Their best match bullets shot out of such necks group 1/4th MOA average at 200 yards.

Besides, perfectly straight cartridges are a bit crooked in the chamber when fired.

 

[fredo]

It doesn't matter if the outside of the case neck is a bit eccentric. That part of the case is not used to center the case neck nor bullet on the bore axis.

Sierra's cases used to test their bullets are that way. Their best match bullets shot out of such necks group

Here the part of my post you didn't quote:

P.S. Make sure your neck bushing is floating in the die. If the stem is snugged down hard against the bushing, it might bind it up & induce runout to your case necks...

Great advice above! Go sloooow, and measure!

Hard to tell with only a photo to reference, but those necks look a bit jacked up. The first part of my post you snipped & responded to was more of a general statement of common knowledge that the OP might not have been aware of.

The latter, which you cut out and omitted, was offering a possible cause for the messed up/rubbing neck. Especially so, if that bent neck happens to be toward the thicker side of an already eccentric neck thickness..

Just trying to help!

 

[Bart B.]

Are you saying the bushing axis may be crooked in the die and bend the case neck?

 

[mr45man]

I had 50 rounds through it before the issue arose. The first 50 were nosler cases out of the box and all shot with no issues. It wasn't till I

This needs to be "splained "first.
Carbon?