Question on neck sizing and tension . . .

[evnglst]

I'm new to reloading, and very much appreciate the quality of posts in this forum, so I hope this question is relevant to you all.

I'm noticing much more consistency in my neck concentricity (.223 rem) when using a full-length die with a carbide size button (as opposed to just neck sizing). The button in the FL die measures .222, while the expander I have used in the past (when just neck sizing) measures .223, and of course, the expander is much longer, which I expect would leave the necks with even less tension.

Question is, how much neck tension am I looking for? Should I also use the neck expanding mandrel after FL resizing with the carbide button expander?

And, is the only way to really test this to do a series of loads using both, and watch to see when I am starting to build higher pressures with each case prep technique?

Thanks for any insights folks wish to share,
George

 

[ShtrRdy]

Tag -- to follow this discussion

 

[philipbrousseau]

i would not use the neck expanding mandrel. i don't think it is needed and if your cases are straight they might not be after using the mandrel. my guess is you are getting .003 or three thousandths neck tension with your brass if it is not work hardened using your fl. sizing die and that is fine. i would full length size and work up my loads for my rifle. measure the inside neck diameter of your fl sized brass and the difference in that and .224 bullet diameter is your neck tension. i doubt that changing neck tension a couple thousandths would make a difference in pressure that you could detect. i am assuming that you do not have a chamber that requires neck turned brass. what kind of rifle and dies are you working with?

 

[Mikecr]

^^^^WRONG^^^^ (every bit of it)
You can't directly measure neck tension right now, as there is currently no tool on the market for this. Adjustments would have to be compared on targets with careful testing.
If you want better tension consistency you'll stop FL sizing of necks, that's for sure.

 

[FURMAN]

There is a ton of research/testing on neck tension. Some cartridges have a preference but the general consensus is .002 "neck tension" is a good start. To get the best loaded ammo without custom dies get some Redding S bushing full length dies. Load a round with the bullet and brass you intend to use and measure the neck outside diameter. Buy a bushing that is .002 smaller than your measurement. This will give you a place to start. Once load development is complete with powder and seating depth you can play with neck tension. I have never needed to. I never use the expander ball. It seems to cause more runout.

 

[rcoody]

There are several different ways to create quality accurate ammo. All of them work. Until you are measuring groups in tenths of an inch I wouldn't worry about it. Lots of things affect your group size besides neck tension. Consistency is the key to all of them.

I would just purchase the Forster benchrest full length sizing die and their seater and be done with that until you really need to measure your groups in tenths

 

[Mikecr]

There is a ton of research/testing on neck tension. Some cartridges have a preference but the general consensus is .002 "neck tension" is a good start.

Apparently 'a ton of research' has failed to express tension as a tensile force, rather than a dimension(such as simple interference fit).
I agree that a bushing 2thou under loaded neck diameter is a good choice to begin. Likely just what you need. But this really means nothing directly about tension, much less '.002" of tension'. For one, the neck downsized to 2thou under cal would spring back to ~1thou under cal once pulled from the die. This is fine, because 1thou of interference fit would provide all the tension brass can actually provide(it's normal spring back). Now what that spring back tension is, like in PSI, is unknown right now. Remember that annealing and work hardening would change it, regardless of interference dimension.

I guess what I'm saying is: it isn't so simple, and we should not base decisions on misnomers here.

 

[FURMAN]

Apparently 'a ton of research' has failed to express tension as a tensile force, rather than a dimension(such as simple interference fit).
I agree that a bushing 2thou under loaded neck diameter is a good choice to begin. Likely just what you need. But this really means nothing directly about tension, much less '.002" of tension'. For one, the neck downsized to 2thou under cal would spring back to ~1thou under cal once pulled from the die. This is fine, because 1thou of interference fit would provide all the tension brass can actually provide(it's normal spring back). Now what that spring back tension is, like in PSI, is unknown right now. Remember that annealing and work hardening would change it, regardless of interference dimension.

I guess what I'm saying is: it isn't so simple, and we should not base decisions on misnomers here.

Yes, The problem is your are just trying to start an argument. Everyone, that I am aware of, in every shooting discipline in the world refers to the busing dimension vs loaded neck diameter as neck tension. Very few people actually care about the physics involved in the actual tension that is being applied to the bullet. If you always prep your brass the same, use the same brand, keep it clean, use the same lube and lubing methods, and anneal or stop using it at the same time. You will have consistent neck gripping force. If you do not you will see it on the target. As far as decisions on monomers I hate to break it to you but bushing size vs loaded neck diameter is the standard to find the neck tension one is going to use. If the OP really wants to understand the dynamics of neck tension there is a great article on accurate shooter.

 

[Mikecr]

Everyone, that I am aware of, in every shooting discipline in the world refers to the busing dimension vs loaded neck diameter as neck tension. Very few people actually care about the physics involved in the actual tension that is being applied to the bullet.

Ok, the whole world is pretending, and 'very few people' care about what neck tension is, how it applies, or how to adjust it.
Should I concede to ignorance is bliss from boastings about that in basis?
I don't know, it's a public forum..
But with interest, I could explain neck tension in more detail than mob notions, which I believe will help folks, and maybe you as well.

 

[dok7mm]

This is certainly an often debated subject by many shooters. rfurman is correct in that most of us use case neck reduction as a common way to express "neck tension". Mikecr is also correct in stating that it is not an accurate way to state how much tension we are actually getting on a bullet.

Like a lot of us, I struggle to eliminate fliers that, when all other variables have been addressed, usually fall back on inconsistent "neck tension" as the culprit.Mikecr is certainly right that we can't really measure this, so we resort to trial and error, until we find an "acceptable" combination for our usage. JMO

 

[rcoody]

Easy! Seating effort is a very good gauge of neck tension. Best bullet seaters are the Wilson in line seater. You use an arbor press like this. Consistent seating effort means consistent neck tension.

K & M Shooting Arbor Press

 

[Mikecr]

Seating force is as close as we have at this point. It indirectly correlates(comparison-wise) with tension, provided perfect control over friction.
I run with a Sinclair mandrel die outfitted with electronic force measure. I use this for what I refer to as 'pre-seating', and I match pre-seating force with all necks prior to seating bullets.
With this, I've learned a good bit about adjusting actual tension versus fools tension.

 

[243winxb]

I did the 45 acp. Other did the 30-06.

In the 223 - Measure the neck, before and after seating a bullet. If it expands .002" after seating, you will have about 45 lbs needed to pull the bullet. Military standard.

 

[243winxb]

Reloading for Semi-Autos and Service Rifles

See Neck Tension from Sierra here > exterior ballistics