Neck Tension and Bushings

[Clarktar]

If you have the same brass (brand and lot) and have two different rifles in the same caliber would the bushing size needed for and F/L resizing die be the same?

Different bullets, but same caliber and same brass...

I don't see how the bushing size should be different between the two but curious what others have found.

Thanks,

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[Hschweers]

Rifle shouldn’t matter from what I understand. Brass and bullet matter. If both bullets are the same diameter (not box stated, measured) then you could use the same bushing. If one is .001” smaller/bigger you’d need a different bushing to achieve the same neck tension, but could use the same bushing in both and have different neck tension by .001” in each load.

 

[Harvey_NW]

It depends on chamber dimensions, if both chambers have the same neck diameter then theoretically the necks should size the same. Measure the neck diameter of fired cases out of both chambers and you'll get your answer.

Edited to add - one could argue that if there was a difference and you used a bushing based off the smaller of the two that the end result of interference should be the same and the neck tensions would be the same. But someone else will argue that will depend on springback and how work hardened the brass is, or if you anneal every firing or not.. Rabbit hole.

 

[Clarktar]

It depends on chamber dimensions, if both chambers have the same neck diameter then theoretically the necks should size the same. Measure the neck diameter of fired cases out of both chambers and you'll get your answer.

Edited to add - one could argue that if there was a difference and you used a bushing based off the smaller of the two that the end result of interference should be the same and the neck tensions would be the same. But someone else will argue that will depend on springback and how work hardened the brass is, or if you anneal every firing or not.. Rabbit hole.

I don't understand how the neck chamber diameter impacts my neck Tension beyond the fact that necks need to not exceed chamber dimension to fit.

Assuming all brass is appropriately sized to fit in the chamber (both chambers being sammi spec) my thoughts are brass neck thickness and bullet diameter are what is needed to choose neck Tension and bushing. And if you are using the same brass in both rifles and Berger 30 cal bullets (different models but same manufacturer and caliber) then the bushing size is probably the same ....?

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[Harvey_NW]

I don't understand how the neck chamber diameter impacts my neck Tension beyond the fact that necks need to not exceed chamber dimension to fit.

Assuming all brass is appropriately sized to fit in the chamber (both chambers being sammi spec) my thoughts are brass neck thickness and bullet diameter are what is needed to choose neck Tension and bushing. And if you are using the same brass in both rifles and Berger 30 cal bullets (different models but same manufacturer and caliber) then the bushing size is probably the same ....?

Even if both chambers are within tolerance but the neck diameter of one is min spec and the other is +.002", that one is getting worked more and could have more springback, resulting in less tension. To a measurable extent, I don't know. Just saying that's a potential variable that may or may not affect the end result.

 

[ResearchinStuff]

doesn't matter according to austin buschman

The PRS Champ’s Load Data & Reloading Process – Austin Buschman Shooter Spotlight Part 3

This article is part of a series that is taking a deep dive with 6 of the very best precision rifle...

precisionrifleblog.com

 

[BDWMT]

I would recommend testing undersized by .004 or .005 than the recommended.002. I’m finding most my hunting rifles have noticeable improvement with more neck tension and I also like the idea of more durable ammunition when feeding from a magazine.

 

[Clarktar]

doesn't matter according to austin buschman

The PRS Champ’s Load Data & Reloading Process – Austin Buschman Shooter Spotlight Part 3

This article is part of a series that is taking a deep dive with 6 of the very best precision rifle...

precisionrifleblog.com

Well he is using neck Tension in a consistent repeatable manner. You not improve precision from one tension to another (.002 vs .005) but maybe it's the repeatably of the same neck Tension...

He is using some fancy dies and bushings regardless.

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[ResearchinStuff]

top tier dies and brass, plus annealing every load. but he hasn't touched his dies in 15 barrels. makes it pretty obvious the OP shouldn't have to either.

 

[SDHNTR]

I don't understand how the neck chamber diameter impacts my neck Tension beyond the fact that necks need to not exceed chamber dimension to fit.

Assuming all brass is appropriately sized to fit in the chamber (both chambers being sammi spec) my thoughts are brass neck thickness and bullet diameter are what is needed to choose neck Tension and bushing. And if you are using the same brass in both rifles and Berger 30 cal bullets (different models but same manufacturer and caliber) then the bushing size is probably the same ....?

Sent from my SM-G973U using Tapatalk

Springback

 

[Harvey_NW]

top tier dies and brass, plus annealing every load. but he hasn't touched his dies in 15 barrels. makes it pretty obvious the OP shouldn't have to either.

Assuming he keeps the brass fired in the individual chambers separate..

 

[rayporter]

if you dont anneal, the number of shots and the pressure on the case affect the neck tension.

this is also tied to the diameter of the chamber neck and will affect the work hardening of the case.