How does neck sizing length fit into reload tuning?

[PddPdd]

I have a Redding Competition die set with a micrometer adjustable neck bushing. For those not familiar with this die it allows you to adjust how much neck length gets resized by the S-bushing. So knowing that this is another parameter for improving accuracy and reducing SD & ES, where does resizing neck length fit into the tuning sequence along with seating depth, primer selection, and powder charge?

If this is relevant to the question, I'm reloading 28 Nosler with annealing, full length resizing, case trimming, neck turning and concentricity check processes.

Thank you.

 

[Tiny Tim]

I believe its all about neck tension and also allows a controlled portion to remain at or near chamber neck dimension to aid in chamber/bore alignment.

 

[Beluebow]

where does resizing neck length fit into the tuning sequence along with seating depth, primer selection, and powder charge?

So far down the list I doubt many, if any could shoot the difference all else being equal.

 

[Mikecr]

Ok, #1 you're not FL sizing. If you were there would be no question about any partial length sizing, because you would be full length sizing. What You're doing is body-bushing sizing.

As far as tune, seating and primer selection are not tuning, but prerequisite to good tuning.
Powder can be used for powder node tuning, or barrel tuning, rarely both. Pick one -best accuracy, -or forgiving load.

Neck tension adjustment doesn't always offer improvements, but it can where you need more powder burning in the chamber instead of X-distance down the bore(with a tension increase). It can lower tension variances (with a tension reduction). The adjustment is nice in that it can help you be sure to never size more neck length than seated bullet bearing.

With this cartridge, after load development at very near full seated bearing length worth of neck length sizing, I backed off sizing length while group shooting. I came to this reduction before MV started changing, so this is where I left the die setting.
I wasn't tuning, but setting minimum tension for the chosen load, to keep tension variance as low as possible.
It's a turned neck, and thicker or thinner necks would have led to a different setting.

Maybe you could tune with neck tension. Maybe you could affect SD.
But if relying on this for tune, your [spring back force x area gripped] better be super consistent. I think it would need to be measured, and right now there is no way to actually do that.
Given this, It's easier for sure to rely on the right powder charge for tune.

 

[PddPdd]

Mikecr,

I was looking forward to your reply and you didn't disappoint. I will need to digest your response a little while before I have a technical follow up.

Thanks much!

 

[Rardoin]

I have tested sizing bushing sizing the entire neck and leaving about 1/3 of the base of the neck untouched by the bushing. I did not see any improvement in groups in tests at 100-300yds and my 600/1000 yard test during matches did not reveal any difference in the pattern of shot fall between strings shot with either treatment. This was in a straight .284/184 Berger hybrid. I did find that the partial sized necks had periodic cases with resistance on bolt closure that was not present with the fully sized necks. I abandoned that experiment as I did not find an advantage in my set-up. You will have to test it in your particular set-up and see what shakes out.

 

[26Reload]

Cannot pressure to the bullet be created in a few ways
1..std lenght..not turned..
2..std lenght..turned..
3..long neck..not turned..
4..long neck turned..
Wouldn't each have a direct variation to how much pressure is exerted on the grasp of the bullet..inreturn..have a variance as to how long the bullet is held by the brass...
Albeit...miniscule differences..but wouldn't each achieve a different barrel harmonics..by way of timing exiting the barrel...

 

[Rardoin]

Cannot pressure to the bullet be created in a few ways
1..std lenght..not turned..
2..std lenght..turned..
3..long neck..not turned..
4..long neck turned..
Wouldn't each have a direct variation to how much pressure is exerted on the grasp of the bullet..inreturn..have a variance as to how long the bullet is held by the brass...
Albeit...miniscule differences..but wouldn't each achieve a different barrel harmonics..by way of timing exiting the barrel...

In theory, absolutely. In practice, your set-up may or may not show differences in how the rifle groups.

 

[PddPdd]

Maybe you could tune with neck tension. Maybe you could affect SD.
But if relying on this for tune, your [spring back force x area gripped] better be super consistent. I think it would need to be measured, and right now there is no way to actually do that.
Given this, It's easier for sure to rely on the right powder charge for tune.
[/QUOTE]

Mikecr,
Regarding measurement of the length of neck getting sized by the bushing, I agree I don't know of a way to measure it but wouldn't trimming a case to a fixed length each reloading after body sizing plus no changes to the S-bushing die engagement keep it consistent?

As a side note, I was wondering if limiting the neck sizing would allow one to avoid sizing the portion of the neck where a doughnut might be forming to some unknown degree and therefore avoid that issue?

 

[PddPdd]

I have tested sizing bushing sizing the entire neck and leaving about 1/3 of the base of the neck untouched by the bushing. I did not see any improvement in groups in tests at 100-300yds and my 600/1000 yard test during matches did not reveal any difference in the pattern of shot fall between strings shot with either treatment. This was in a straight .284/184 Berger hybrid. I did find that the partial sized necks had periodic cases with resistance on bolt closure that was not present with the fully sized necks. I abandoned that experiment as I did not find an advantage in my set-up. You will have to test it in your particular set-up and see what shakes out.

Rardoin, Thanks for sharing your experience!