purpose of neck turning

[Willoughby]

someone please exsplain to me the purpose & process of neck turning
is neck turning just for reducing thickness of brass
after forming brass from a larger diamenter caliber ?
say forming 6.5 saum brass from 300saum?
or is there more to neck turning than that
thanks for any responces

 

[Immike]

By having all the necks the same you have a constant on the release of each bullet.

 

[savageshooter86]

a lot more than just that reason.

1. Uniform neck thickness for better(consistent) neck tension. Remove 100% off necks to a determined neck wall thickness
2. To fit the brass in tight neck chamber
3. "Clean up" neck thickness on brass to have more uniform neck tension. Some remove 75% or so off neck to clean up neck

I had a unturned 308 Lapua case and seated my bullet. Runout was 6 thous. Same set up and everything runout on turned neck brass the needle didn't move. So I believe it helps with runout too

 

[Erik Cortina]

a lot more than just that reason.

1. Uniform neck thickness for better(consistent) neck tension. Remove 100% off necks to a determined neck wall thickness
2. To fit the brass in tight neck chamber
3. "Clean up" neck thickness on brass to have more uniform neck tension. Some remove 75% or so off neck to clean up neck

I had a unturned 308 Lapua case and seated my bullet. Runout was 6 thous. Same set up and everything runout on turned neck brass the needle didn't move. So I believe it helps with runout too

#2 is only due because the tight chamber is meant for turned necks. You don't turn brass to use a tight chamber, you use a tight chamber to use turned brass. Dig?

Uniform neck tension is one reason, but the other is for concentricity.

 

[Phil3]

I am a novice, but think I can answer this reasonably well, which is not to say the previous responses are incorrect. They aren't.

Consider all objectives. These are the three primary ones I know of. There could be more.

Equal Bullet Tension: An unturned neck is likely to demonstrate varying neck wall thickness. For example, .011” in one place on the neck and maybe .013” in another place. This will result in in non-uniform tension on the bullet.

Case to Case Tension Consistency: One case may measure .011 to .012”, while another case may measure .012 - .014”. The two cases both have non-uniform bullet tension and probably exert a differing amount of total tension.

Concentricity: If the case neck exterior is concentric to the case body, (due to sizing on the outside of the neck), and the neck thickness varies, then the interior of the case neck (or the bullet) is NOT concentric with the case body. With consistent neck wall thickness (from neck turning), the exterior wall and interior wall of the neck are concentric with one another.

It should be said that tight-neck chambered guns are designed to use turned brass, and in that case, you have to neck turn just to chamber the round. The chambers are cut to precisely fit the smaller diameter necks resulting from neck turned brass.


Phil

 

[LHSmith]

CONTROL.......turning case necks give the shooter who wants absolute accuracy the ability to control the variables typical of factory brass....allowing them to better control neck tension, concentricity, and optimize the "fit" of the loaded round to the chamber neck area (i.e. amount of clearance between the two).

 

[Barlow]

Can you guys that neck turn cases for factory sporter rifles prove that it makes a significant enough difference at normal game ranges (up to350 yards) to make it worthwhile to go through the pita of neck turning? Barlow

 

[savageshooter86]

Erik I dig ya. That's what I meant to say but you nailed it on the head man

I would think for hunting in a factory chamber with a sporter barrel it wouldn't be worth the time and hassle to turn the necks..... Just my 2 cents

 

[Erik Cortina]

I would think for hunting in a factory chamber with a sporter barrel it wouldn't be worth the time and hassle to turn the necks..... Just my 2 cents

+1

 

[tenring]

I neck turn only for tight neck chambers. Never for hunting rifles; its an unnecessary PIA.

 

[CPorter]

I have demonstrated it to myself. I have targets running back to the 90s and have kept a spreadsheet with the group radius for them. The average shrank during the period I was searching Benchrest.com and PresicionShooting for ways to move up in the local long range fun shoots. Looking at the Remington brass I was using I had noticeably eccentric neck thickness and neck turning was the solution. I got my Remington 700 VLS in 243 Win to where I fairly consistently shot 1/2 inch 5 shot groups and regularly got in a 3/8 inch group. One hole groups happened enough that I am sure the gun and the loads are better than me on the trigger.

Enough proof? Try it with some of your own brass, keep a batch without turning and use both for practice. Scan them and use the software mentioned on the board to measure the group radii and figure it out.