Neck Tension

[SergeantD]

Ok first off I'm no newbie to reloading but I always love to know how others are doing things. Question: How do you know when your neck tension is correct or enough and how do you go about checking it?

Once I get enough answers, I'll let you know what the Ballistician's say.

 

[Jud96]

Typically neck tension runs between 0.001-0.003. Most guys stay around 0.002-0.003 for best results with hunting and field rifles. You check it by sizing a piece of brass, measure the outside diameter of the neck after sized. Then seat a bullet in that sized case and measure the outside diameter of your case. If your sized case was 0.310 for example and it's 0.312 after seating a bullet, then you have 0.002 of neck tension. All of the standard dies I use size the brass to have 0.0015-0.002 neck tension. The only way to adjust neck tension is to buy bushing sizing dies. With those, seat a bullet, measure the neck O.D., subtract how much neck tension you want and order that bushing. So again, 0.312 loaded neck diameter and you want 0.003 of neck tension, then order a 0.309 bushing.

 

[FURMAN]

Jud96 did a great job explaining how shooters/reloaders use neck tension. It has been a while since I have had regular dies but everyone I measured was waaaay more than .002 or .003. I have since gone to bushing dies only. I run .002 and have never had a problem getting the ES/SD and accuracy I expect so I have never experimented.

 

[Barrelnut]

Once I get enough answers, I'll let you know what the Ballistician's day.

HaHa. On what day did they say? Hope you took good notes... Why not just pass this cherished knowledge along and allow us to ask questions and comment?
Sorry don't feel like playing.

 

[Dirtdevil]

I prefer to use expander mandrels. There are a couple places that have them in any diameter you want Can control the amount of neck tension plus the big gain I see is it leaves your neck true and straight unlike dragging over an expander ball Size the case with no expander in it Run the case over the mandrel and loadem

 

[FURMAN]

I prefer to use expander mandrels. There are a couple places that have them in any diameter you want Can control the amount of neck tension plus the big gain I see is it leaves your neck true and straight unlike dragging over an expander ball Size the case with no expander in it Run the case over the mandrel and loadem

I know some claim to get better runout this way but I have tested it with multiple cartridges and brass manufactures with Redding and Whidden dies and I always get less runout with bushing dies and no expander ball. I revisit it every couple of years but the bushing with no mandrels always wins for me. It can't hurt to experiment.

 

[bigedp51]

Expander Ball Kits
The Whidden Gunworks Expander Balls typically allow the shooter the opportunity to adjust the neck tension from .001″ to .005″. The Expander Ball Kit comes with five Expander Balls. Each kit includes an Expander of the chosen caliber and decreases in size by .001″. Example: If an Expander Ball Kit for .243 caliber is ordered, the kit would include Expander Ball sizes .243, .242, .241, .240 and .239.

 

[Dirtdevil]

I know some claim to get better runout this way but I have tested it with multiple cartridges and brass manufactures with Redding and Whidden dies and I always get less runout with bushing dies and no expander ball. I revisit it every couple of years but the bushing with no mandrels always wins for me. If you are running quality brass that's probably true. Or if you turn the necks to a uniform thickness the bushing die will probable do just as good But when your brass has uneven thickness in the necks run out will show up with a bushing die. But hey that's the fun of experimenting

 

[FURMAN]

Dirtdevil you quoted me but edited the quote. I really do not care but it may confuse future readers of the thread.

I do not turn necks but I do buy the best brass I can. I have turned necks in the past and could see no difference in ES/SD or accuracy so I no longer do it. My neck turning equipment gathers dust.

 

[tdot]

Dirtdevil you quoted me but edited the quote. I really do not care but it may confuse future readers of the thread.

I do not turn necks but I do buy the best brass I can. I have turned necks in the past and could see no difference in ES/SD or accuracy so I no longer do it. My neck turning equipment gathers dust.

I dont think DirtDevil meant to edit your post. I think when some people Reply to posts, they inadvertently add their comments into the original quoted Post. Instead of before or after the quote. It seems to be an easy mistake to make.

 

[FURMAN]

I dont think DirtDevil meant to edit your post. I think when some people Reply to posts, they inadvertently add their comments into the original quoted Post. Instead of before or after the quote. It seems to be an easy mistake to make.

I am confident it was an accident. I was just pointing it out.

 

[MagnumManiac]

My comp rifles run .0015" tension and the bullets are .010" into the rifling.
More tension than this is not necessary.
I ran eccentric and concentric loads in a round robin and individually in a rifle that is a genuine .1MoA shooter.
No discernible difference in AVERAGE group size over 10 10 shot groups could be determined at 600yrds. These were tested at different times on different days, just like a comp is run.
I take no measurement on concenticity anymore. Don't even think about run out anymore.

On my hunting rifles, tension runs .002-.004" on AVERAGE.
I find tension, or resistance fit, varies even after annealing, mandrel sizing or even using an expander.
I found the most consistent method was a honed neck FL die and modified expander that only moves the neck a maximum of .002" from sized to being run through the expander. The straightness is better than a bushing, where ANY imperfection is exacerbated on the inside of the neck.
I prefer the imperfections be on the OUTSIDE of the neck personally.

Cheers.

 

[TheLongRanger83702]

Ok first off I'm no newbie to reloading but I always love to know how others are doing things. Question: How do you know when your neck tension is correct or enough and how do you go about checking it?

Once I get enough answers, I'll let you know what the Ballistician's say.

My Wilson dies are set with a neck bushing at .002 under. That being said you're going to have to have brass with consistent neck wall thicknesses to make using this method work effectively. I've found Nosler brass fits the bill here. Good luck.

 

[misterc01]

Interesting thread. I measure the neck diameter first time I reload the brass to ensure it is consistent at four points. If not, then I turn the neck just enough to take the high spots off to to make sure it is round. I neck size mine to get .003 neck tension. As long as everything is consistent, then I can make changes that yield positive results. CONSISTENCY is what I am shooting for (Oops - that was an unintended pun - but funny!)