neck tension

[nhdog]

For years I've used both Redding competition dies as well as the Lee collet dies for my reloading and with both I find that at times I fell that there is a difference in the amount of neck tenson when seating a bullet, not much, but a difference.  Now that may just be me and my perception, but just how much does the amount of neck tenson effect bullet velocity and accuracy?

[Land_Owner]

There is a train of thought that consistent neck tension should be the rule rather than the exception.  Turning the necks to eliminate thick spots and to accentuate a consistent grip around the full circumference of the bullet should aid mechanical accuracy.  This is not unlike concentricity, which starts the bullet down the middle of and in parallel line with the bore.  Out of alignment jump to lands created by inconsistent grip (secondary concentricity) would tend to pull the bullet to the tight side creating a different pressure wave down the barrel.  How much effect consistent grip affects velocity and accuracy is IMO probably not measurable.  Do all you can to make the mechanism truly accurate, then do your best.  Humans are the weakest link in the accuracy equation.

[Catfish]

As Land owner said, the problem is in the thickness of your brass not being consistant. If you`re happy with your accuracy, don`t do anything. If you feel the need to trun your case necks for a factory chamber you will shorten the case life and the more you take off the more it will shorten. The thinner necks will also reduce the amount of neck tention you have. I have several tight necked gun that require neck turning, but do not turn necks on any of my factory chambered rifles. If you feel you must turn necks, just take off the high spots.

[necchi]

I mentioned this in another topic but I think it belongs here too.
 I've noticed a differance in neck tention useing my dies too, and I think it has to do with the amount of time between sizing and loading.
 Brass has "spring back" properties, it wants to return to it original shape after sizing. The stuff will continue to move for the first 24 and up 72hrs. The differance in tention I've felt, is when I prep a bunch of cases then don't get around to loading them for days or even weeks ( just preping in advance ). It's tuffer to seat after 24hrs.
 I think the added difficulty seating in a tighter necks adds to run-out issues and it's the runout that causes bigger groups down range.
 So I guess I've learned to just prep what I need or can load within 24 hours

[huntducks]

I mentioned this in another topic but I think it belongs here too.
 I've noticed a differance in neck tention useing my dies too, and I think it has to do with the amount of time between sizing and loading.
 Brass has "spring back" properties, it wants to return to it original shape after sizing. The stuff will continue to move for the first 24 and up 72hrs. The differance in tention I've felt, is when I prep a bunch of cases then don't get around to loading them for days or even weeks ( just preping in advance ). It's tuffer to seat after 24hrs.
 I think the added difficulty seating in a tighter necks adds to run-out issues and it's the runout that causes bigger groups down range.
 So I guess I've learned to just prep what I need or can load within 24 hours

I'm sorry but I don't buy into that idea I have resized brass years before and can't feel a diff and if you can tell neck tension just by pushing a bullet into a case after it sits for a few days or weeks WOW 

[Land_Owner]

I will agree that all folks do not sense "things" the same way.  I like to say that "I can not see the world through your eyes" ('cause that would leave you blind...hehe).  I can only guess that what I see is nearly the same as what you see; but who can say for sure?

Sensitivity to press resistance when seating a bullet is something I can "buy into".  It is not out of the realm of possibilities, particularly when the individual is constantly seating hundreds or thousands of bullets repetitiously.  As is most things formed by habitual methods, there is a noticeable resistance that, should it change, would lend one to pause for a reason. 

The OP uses two different dies.  Supposedly for the same caliber.  I would guess that one is just shy of the other diametrically.  Maybe 0.001" wouldn't be too small.  One one-thousandths.

[necchi]

Well, I ain't tryin ta sell nuthin huntsducks, 
 Springback in brass cases is a real and measurable thing, esp with bottle neck cases. I have seen the differance in groups change,  with the condition of the brass I load.
I only offer what I have found out of my own research and experiance.

 I hope your method of loading for years works well for you.

I'll load my ammo for me,, the way I do it,, for me. Your milage may very.

[JustaShooter]

You aren't the only one necchi - I've felt it too, and I've seen where other, far more precise shooters have noticed it as well:

http://bulletin.accurateshooter.com/2010/02/neck-tension-bullet-seating-and-the-time-factor/

Just a Shooter

[necchi]

Thanks for the link, that forum has alot of great archives in written artical form like that. Good Stuff.
Varmint Al's has some really good info out there.
There's alot if ya wanna look, but ya do hafta weed through some bull. But when you see the same info repeated at several places, answering the same kind of queary's it tends to have a little meat too it.

I guess it's about how accurate a guy wants, Hunters have different goals then Target shooters,, then there's the Bench Rest guy's  Wow!

[Lloyd Smale]

im not as anal as some handloaders. I dont have time to be. Just to many guns and not enough time to shoot them all as it is and i hate wasting time on trivial loading practices. The only time i turn necks is rifle brass ive necked down from a larger caliber like making 2506 from o6 or 257wby from 270 wby. Last couple days ive loaded about a 1000 308s for the ars. All mixed brass. About the only thing i do for case prep is keep my cases trimed to lenght. You really notice the differnce in case neck tension from one round to another loading like that. That been said that load i use even in mixed brass has shot consistant 3/4 inch groups out of my ar10 and how accurate does a guy need a rifle to be. Sure i may knock another 1/4 inch off my group size if i got anal about case prep and used matching brass but i could probably shoot this 1000 rounds and load it back up and have it ready to go again in the time it took me to prep those cases. Bottom line is I reload so i can shoot more. Reloadings a job and shooting is a passion. Ill take range time over loading room time ANYTIME!!

[FW Conch]

I seat all my bullets with a LEE hand press. If you really want to get a a feel for neck tension, try it. 

[wncchester]

"I can not see the world through your eyes"

I can't see the world the way some people see it 'cause I can't get my head where their's is.

Ref felt "bullet tension" I doubt anyone but a BR guy trying to shrink .25" average groups to .20" will see any useful effect on target.

[necchi]

I think it plays into it a bit more than that,
 More like sub-MOA at 200 instead of 4"s.
 Neck tension is right up there with crimp and not to crimp or how much to crimp. It's simply another variable that one either pays attention too or not. The individuals choice.
Alot of neck tention is going to affect how the powder burns as opposed to the same charge with little tention.
   People all over are using neck dies an FL dies and bushing dies by different makers all for the affect it/they have on the neck,, and all that IS about the tention the neck is placing on the bullet.

 Is there one right way or one wrong way? No. But it is something very simply noted that with a small amount of awareness can be treated as another variable in the entire loading game. And as with all variables keeping that one at least consistant while your playing with other variables helps narrow down the possibilities.

 I didn't get into loading just to shove the handle up an down to have a bunch of ammo to shoot cheap. I also didn't get into loading to become an F-class champ, but I do enjoy being able to load stuff for my factory guns that out preforms factory ammo. Paying attention to the simple variables and keeping things consistant has allowed me to do that. The condition of my brass is one of those thing for me. It's easy stuff, 
It's the K.I.S.S factor, Right?

[FW Conch]

+ 1 necchi - well put 

[SHOOTALL]

When a primer ignites the first peak in pressure is when enough pressure is made to cause the bullet to move forward . The more nech tension the higher the pressure . If different pcs of brass in same group of brass have different neck tension for what ever reason the bullet will be released at different times . This will be noticed down range . Brass at different temptures can display different neck tension even if all else is the same. The question is how much difference and will it effect the intended use ? For long range and benchrest shooters it is/might be critical . For plinker and hunters maybe not so.

[SHOOTALL]

I would also suggest that this may be one of many  of the reasons different factory lots of ammo shoot different.

[Buckskin]

I notice a big difference in neck tension from time to time.  Especially when full sizing brass.  Now what that is from I don't know, harder/softer brass is my guess.  I don't anneal and am leaning towards not ever doing it.
When I find some that load harder, they go in my seconds pile as I've found that almost always they have more runout than when they slide right in, typically have some shaved copper not to mention likely having more tension on the bullet causing higher pressure and inconsistency.   The key to loading precision ammo as everyone knows is consistency.  That is consistency in every little knit picking step, component, technique, etc.

I have noticed that with the Lee Collet dies that neck tension is way more consistent and less runout overall than with full length sizing.  Now saying that, I have never used Redding or any other competition dies.  I would rather spent the $30 on the lee set collet set..

[helotaxi]

If you think about how a collet die works, it makes sense that it would be more consistent.  Unlike other types of dies that press the neck undersized and then push it back out with an expander button, the collet die only works the neck once when the collet squeezes the neck around a mandrel.  The neck is effectively swaged into the desired shape with the desired internal dimension.  Unlike other neck sizing methods, spring-back is not an issue and neck wall thickness is not as important as a result.

Neck tension is all about consistency and a collet die removes many of the variables that lead to inconsistency.  Needless to say, I'm a big fan of the Lee collet neck sizers.