Monitoring Neck Tension in ft-lbs as opposed to neck size

[GunnyUSMC]

I, like just about everyone else, approach neck tension based on how much i am resizing the neck using a combination of neck sizing bushing and a mandrel. I also use a K&M Arbor Press with Dial gauge when seating my bullets. I typically use the gauge just to monitor seating consistency. When preparing for a match, i will separate my loads based on seating resistance derived from the dial gauge.

I did an experiment with my 6.5 creedmoor whereby i confirmed some (very slight) resistance when sizing my neck with the mandrel and then slightly reduced the size of my CM case neck for some cases but still used the same mandrel in the neck. This test resulted in seeing a slightly higher pressure to seat my bullet.

After this test, i started paying more attention to the bullet seating resistance in terms of ft-lbs as opposed to neck size/mandrel. I also use this number to help me compare MV/SD/ES of different loads based on bullet seating resistance.

Just wondering if anyone else pays attention to ft-lbs of resistance when seating bullets.

My theory is that performance of slower burning powders can potentially benefit from tighter neck tension and am looking for real data to make that comparison as opposed to just relying on the bushing/mandrel size.

 

[ELR LVR]

Yes In the rifles I consider my most accurate ones, I go for a certain "feel"
As well as Consistency in that feel
My necks are turned down to assist in tuning the consistency in that "Feel"
When I measured this "Feel" it turned out to be 1 lb of force required
And with using powders from W748 Speed to H1000 Speed, same neck tension
(Meaning H1000 did not need an abundance of neck tension to get going or burn clean)
(with 1 lb of neck tension bullets still stay same OAL in a magazine under recoil also)
-------------------------------------------
In Larger Calibers however such as 30/06 or 300WM I did not do any of these things and could not believe how much force is required to punch a bullet into the neck of those cases
they still shot decent groups
............Clover Leafs
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So I don't know how much it matters as long as it is consistent.
I just don't like it when it feels like you're about to crush the shoulder of your brass when seating a bullet
so I like light neck tension, as well with light neck tension it is much easier to "feel" any change in force required
When I feel this difference, it is very evident and means it is time to anneal my brass

 

[GunnyUSMC]

Yes In the rifles I consider my most accurate ones, I go for a certain "feel"
As well as Consistency in that feel
My necks are turned down to assist in tuning that consistency in that "Feel"
When I measured this "Feel" it turned out to be 1 lb of force required

oh wow!!! just 1lb!! is that ft-lb?

I ask because my gauge reads an average of 25 ft-lbs for my .223, 40 ft-lbs for my 6.5CM and 55 ft-lb for my .338 Edge.

 

[ELR LVR]

Your foot/lbs seem to correlate to the case sizes increasing , which is what I found as well
Thicker brass, as case size increases
And yes,, I meant to say 1 lb of force, but that is the force measured on the end of my press arm
...and would not be the amount of ft/lbs at the actual bullet given leverage ratio's and such.
The weight of my press arm allllmost seats a bullet itself, I just have to give it a little nudge with one finger and the bullet glides in almost effortlessly. This method has also helped reduce bullet runout. often being no more than .001"
Some might suggest this is too little tension, but it has worked for me and gives me more of a known constant with regards to neck tension. (Basically I dont like differing neck tension being a factor in the powder initiation, so go for as light as tension will hold a bullet without the bullet moving under recoil,
This has also eliminated shaved copper when seating a bullet, which cannot be good considering Center of gravity changing around center of form if that happens)
I go through great lengths to prevent shaving copper off the surface of the bullet including not just chamfering inside with a VLD reamer, but then going back and smoothing/polishing the inside with steel wool.)

 

[GunnyUSMC]

ahhh... gotcha

I am not using my regular press for seating. I am using a small standalone arbor press. I suspect that if I were to seat in my regular reloading press, it wouldnt take much to seat my bullets either, especially the .223.

 

[SteveOak]

Neither method accounts for all of the forces in play.

Measuring force required to seat the bullet does not distinguish friction from the force of spreading the brass. Higher brass to copper friction combined with softer or looser brass could measure the same as stiffer or tighter brass with less brass to copper friction. What are you actually measuring this time?

Also, I am pretty sure you are not measuring foot pounds. Foot pounds is force applied across a distance. The presses I have seen only measure force, not force/distance.

Using a neck bushing with (what I do) or without a mandrel does not account for the malleability of the the brass, or lack therof. It does remove friction from the equation.

 

[Owens85]

The thing with the seating force gauge is that even with the same amount of neck tension it can differ because of the condition of the inside of your necks (friction). Lubing inside of necks, tumbling brass in different types of media, brushing inside of necks to not doing anything to the inside of the necks will show different numbers on gauge with same size inside neck diameter. Saying all this I do take it into account when seating bullets . If my force is the same as last time using same method of prepping brass then I knew my brass necks are in the same condition as the last time I prepped them. High or low ones go to a fouler pile.

 

[Chris Edmondson]

I, like just about everyone else, approach neck tension based on how much i am resizing the neck using a combination of neck sizing bushing and a mandrel. I also use a K&M Arbor Press with Dial gauge when seating my bullets. I typically use the gauge just to monitor seating consistency. When preparing for a match, i will separate my loads based on seating resistance derived from the dial gauge.

I did an experiment with my 6.5 creedmoor whereby i confirmed some (very slight) resistance when sizing my neck with the mandrel and then slightly reduced the size of my CM case neck for some cases but still used the same mandrel in the neck. This test resulted in seeing a slightly higher pressure to seat my bullet.

After this test, i started paying more attention to the bullet seating resistance in terms of ft-lbs as opposed to neck size/mandrel. I also use this number to help me compare MV/SD/ES of different loads based on bullet seating resistance.

Just wondering if anyone else pays attention to ft-lbs of resistance when seating bullets.

My theory is that performance of slower burning powders can potentially benefit from tighter neck tension and am looking for real data to make that comparison as opposed to just relying on the bushing/mandrel size.

I have used ft-lbs (aka Work) extensively to sort rounds into groups and really don't see much fertile ground. The problem I see with using Work as an affinity proxy is it doesn't know when, and why the resistance force came about. An absurd example: one case was overlooked during chamfering, another case has a donut forming, they both require similar effort (Work) to seat a bullet but other than that, they have little in common. In this example, the press chimp can easily tell the difference; the 'puter, not so much.

Having said that, with a reasonable sample size, Work will serve well to organize finished rounds into groups. Even with that byproduct, it confounds me why a bottom-of-the barrel group outshoots a Nobel-Peace-Prize group sometimes, my rifle enjoys embarrassing me, lol.

 

[TIMO]

Just my .02
I use a pin gauge after sizing to sort them prior to charging and seating. I believe the reason I have a few variations is mainly due to my neck turning as I have a few pieces that the neck thickness is a little off. Usually it varies not more than .0005 to .00075 (hope my decimal point is in the right place). I also use a basic arbor press (Harrells) for seating and can feel the difference with those where the necks are a fraction thicker. I should just mark them and use a different bushing when sizing them, and use them as sighters/foulers.

A 30BR likes "neck tension ".... a discussion ensues.

There is only one person I know locally who shoots 30BR. First time out with my 30BR he made the statement you see in my title. I just nodded and didn't say much. So while I hate the term "neck tension" I absolutely agree your reloading technique can definitely 100% change the force required...

forum.accurateshooter.com

Tim

 

[Sandstorm]

I should just mark them and use a different bushing when sizing them, and use them as sighters/foulers.

If your competing just use them for sighters as I do. I don't clean my brass, but do brush the necks after annealing prior to seating on a Arbor press and get fairly smooth seating and even pressure on all my Lapua brass. New brass and super clean brass is extremely sticky and seats inconsistently if the necks are not prepped or dry lubed in some fashion...just my 2c

 

[Owens85]

Another thing I'll add is when you have inconsistent seating force(friction) it can throw your seating depths off. If one seats smooth and one seats sticky or just harder let it be inconsistent inside neck diameter or just inconsistent inside neck condition or if you forget to chamfer your brass it will show up on that gauge and your seating depths will be off.

 

[JEFFPPC]

Another thing I'll add is when you have inconsistent seating force(friction) it can throw your seating depths off. If one seats smooth and one seats sticky or just harder let it be inconsistent inside neck diameter or just inconsistent inside neck condition or if you forget to chamfer your brass it will show up on that gauge and your seating depths will be off.

I disagree.I closely monitored neck tension with a K& M set up for 2 seasons and part of a third shoot from 100 to 1000 yards before deciding that for me it was non productive and quit using it. It has no effect on properly prepared brass and bullets in regard to seating depth. I seldom have a loaded round off more than a half a thousandth plus or minus. If you think you can judge neck tension strictly by feel in relationship to gauge numbers you are incorrect, but does it matter, yes but I don't believe to the degree some believe.If I was younger I might try sorting cases by fps which IF it is repeatable makes more sense to me. I once sorted brass bu volume until repeated 10 shot groups told me it did not make much difference. In fairness that was not with a bench rifle but a very accurate Silhouette rifle. It's easy to get on various loading tangents but it's good to test with an open mind what works for you. So in this case my finding is neck tehsion does not have any bearing on seating depth in my reloading process which is 35 or 36 steps as I remember for each loaded round and no longer measuring neck tension while seating proven by the numbers my loaded round measure.

 

[Owens85]

I disagree.I closely monitored neck tension with a K& M set up for 2 seasons and part of a third shoot from 100 to 1000 yards before deciding that for me it was non productive and quit using it. It has no effect on properly prepared brass and bullets in regard to seating depth. I seldom have a loaded round off more than a half a thousandth plus or minus. If you think you can judge neck tension strictly by feel in relationship to gauge numbers you are incorrect, but does it matter, yes but I don't believe to the degree some believe.If I was younger I might try sorting cases by fps which IF it is repeatable makes more sense to me. I once sorted brass bu volume until repeated 10 shot groups told me it did not make much difference. In fairness that was not with a bench rifle but a very accurate Silhouette rifle. It's easy to get on various loading tangents but it's good to test with an open mind what works for you. So in this case my finding is neck tehsion does not have any bearing on seating depth in my reloading process which is 35 or 36 steps as I remember for each loaded round and no longer measuring neck tension while seating proven by the numbers my loaded round measure.

Well I disagree with you. Take a case and run a brush through a case neck vs one that hasn't had a brush through it and seat a bullet . The one that didnt have a brush put through it will have a higher seating force in which can vary seating. Maybe not by much but in BR I strive to have everything the same. But yes cases that are prepped properly it doesn't play a effect on it. But no way do I use 35 to 36 steps to process my brass .don't see the need to . To each there own. My process works for me.

 

[quest450]

I used seat my bullets by feel but it wasn’t accurate enough for my liking I like to see numbers and AMP press does that very well it eliminates human error and it shows how uniform the neck prep is, it was a game changer for me as an example here’s 200 rounds prepared for a match

 

[shoot4fun]

A little dab of Hornady One Shot on a swab used to lube the inside of the neck makes a big difference in how the gauge on my 21st Century arbor press reads.
But, necks all sized with the same bushing and final sized with the same mandrel, I wonder sometimes if that changes actual neck tension or just reduces seating pressure.

 

[Owens85]

A little dab of Hornady One Shot on a swab used to lube the inside of the neck makes a big difference in how the gauge on my 21st Century arbor press reads.
But, necks all sized with the same bushing and final sized with the same mandrel, I wonder sometimes if that changes actual neck tension or just reduces seating pressure.

I think it just changes setting pressure. I believe it has the same amount of neck tension on the bullet. Just the lube helps smooth things out (friction )when seating. Imo.

 

[JEFFPPC]

Well I disagree with you. Take a case and run a brush through a case neck vs one that hasn't had a brush through it and seat a bullet . The one that didnt have a brush put through it will have a higher seating force in which can vary seating. Maybe not by much but in BR I strive to have everything the same. But yes cases that are prepped properly it doesn't play a effect on it. But no way do I use 35 to 36 steps to process my brass .don't see the need to . To each there own. My process works for me.

You need to reread my post. I did not say to prep the brass which is only part of the process. But as always we each chose our method. I just think it's important to test and see what works for you as opposed to jumping on something you read.

 

[TC260]

A little dab of Hornady One Shot on a swab used to lube the inside of the neck makes a big difference in how the gauge on my 21st Century arbor press reads.
But, necks all sized with the same bushing and final sized with the same mandrel, I wonder sometimes if that changes actual neck tension or just reduces seating pressure.

Friction force is a simple equation, it's the normal force (N) times the friction coefficient (µ) between the two surfaces. F = µ x N. The lube just lowers the friction coefficient, the normal force (neck tension) stays the same.

 

[Owens85]

You need to reread my post. I did not say to prep the brass which is only part of the process. But as always we each chose our method. I just think it's important to test and see what works for you as opposed to jumping on something you read.

I agree with the part of works for you!!! As what I've stated I've tried and tested and it works for me!!! Should always test for yourself the paper don't lie.

 

[Chris Edmondson]

I used seat my bullets by feel but it wasn’t accurate enough for my liking I like to see numbers and AMP press does that very well it eliminates human error and it shows how uniform the neck prep is, it was a game changer for me as an example here’s 200 rounds prepared for a match



View attachment 1640026

I agree it's nice to have the data but, how does the data guide you when it comes time to pull the trigger?

Nice seating BTW