Neck Tension

[spclark]

OK I've read what you've posted since my reply from yesterday. It's clear to me your background & experience is such that you're practiced with measuring nomenclature sufficient for other, less skilled folks to believe what you've written.

I guess my side of the discussion boils down to how precise (how accurate bears on consistency of measurement here) a serious reloader needs to be to have confidence in the merits of their particular reloading practices.

Most don't have the training or patience to carry things to the point you choose to. I for one am not sure it's necessary to do so in that our choice of 'particle accellerators' aren't anywhere close to the kind that demand tolerances on the order of 0.00005" (that's 5 hundred thousandth's of an inch, the single Significant Figure here the 0 to the left of the 5) to satisfy our need for accuracy on target.

As for the degree of annealing of your cases? Do you have access to the kind of metallurgical testing that could effectively quantify this parameter? That'd be useful info when you're timing variations in dwell time to 0.2 seconds. Then of course you also must correlate the variability of your heat source, case handling, the consistency and initial hardness of cases being processed.... Pretty tedious stuff unless your hobby demands that kind of precision for satisfaction.

I can believe that case production operations could support that level of capability but for my needs it's well beyond where I'd cease worrying about it.

 

[jlow]

Spclark – thanks for the input.

First, I don’t think for most reloaders, you need to turn your neck to the degree of accuracy that I have been doing. To be completely frank, I am not convinced that I need to be able to do this for reloading. The main reason it is useful for me right now is that it helps me to diagnose what variables are affecting my MV ES/SDEV i.e. it now has told me that I indeed have a roundness problem. It may well be when I finally figured out my problem, I may conclude that turning neck to within 0.0002” precision is not a factor, right now I don’t know this one way or another.

As for annealing, I must say that I am in somewhat of a quandary. I have a BenchSource and I anneal going by what the experts that build the machine has taught me to do but I have no way to directly quantify how consistent the end results are. There are methods to do this but they are truly very expensive and completely outside the reach of even the most OCD reloaders. Would love to hear more about this myself.

 

[spclark]

Spclark – thanks for the input.

You're most welcome. Again I agree with everything in your last post. I took to case annealing when my shoulder bump was too inconsistent for me to put up with. Resolving that lead me to look to neck turning for more consistent neck tension, yet another reloading variable but one with less potential to affect inherent accuracy, at least in the 'sling & match sight' games I enjoy. Were I involved in BR stuff, or serious F-Class I might come to feel differently.

As it is though I still want to know my ammunition is capable of the kind of accuracy I expect to hold myself to on a 10" dia. X-ring @ 1,000 yards. Beyond a certain point increased precision achieved in reloading has to effect a diminishing return on paper.

 

[jlow]

Thanks! We are working pretty much along the same line. Good luck with your efforts!

 

[LHSmith]

jlow- when I was in product engineering it was common practice to specify tolerances on the engineering drawings as follows: fractions = +/- 1/16" unless otherwise specified
decimals x.xx = +/- 0.10" " " "
x.xxx = +/- 0.010" " " "
x.xxxx = +/- 0.0010" " " "
Perhaps you can see my dislike to use insignificant numbers behind the decimal point......If misinterpreted an insignificant $50 part could easily become a $1000 item....especially if the item was sub-contracted out and the in-house machinist was out of the loop to question the tight tolerance......multiply this misinterpretation by 1000 parts and you are on the outside looking in.
Likewise, there is a good chance that your insistence to list to the 5th decimal (because" the last one is an average"-your words) will be misinterpreted as having significance.

 

[jlow]

LHSMITH – Don’t have a problem with your dislike. Frankly coming from the scientific field, we also “don’t do it that way” for the very reason you stated. For what we do, this is what we use i.e.

0.01g = 1 mg
0.0001 g = 1 microgram
0.0000001g = 1 nanogram
0.0000000001g = 1 picogram

However, when I first started to post on gun forums, I quickly learned that if I try to do this "my" way, people gets very confused and frankly just plain unhappy because they all are more used to the 0.001” setup. I actually remember a very long thread on this board where it took me three pages of posting to untangle the confusion caused by this. :

So I have tried it both ways, and have learned that I cannot please everyone especially myself, thus the reason for what I use today. I hope you understand.

 

[amlevin]

From where I come from, all those extra numbers are called "Picking Fly Poop out of the Pepper".

I'm surprised people even think this small when it involves a mechanical device which can change dimensions just from the first round to the 10th round due to temperature.

 

[jlow]

Dude, as my students like to say, unfortunately small is a relative term!

For instance, if we are measuring the outside diameter of a 223 case close to its head, SAAMI-spec tells us that it should be 0.3319” in diameter. Now if it was 0.00072” wider, what would be the consequence? First, that is 0.22% difference in diameter, but I would say NOTHING, in fact if you check your stash, there would likely be greater variations than this just coming from the factory and that extra diameter would not affect the seating of your case into the chamber or accuracy of the fired round. So "Picking Fly Poop out of the Pepper" would certainly applied here. ;D

Now, let’s look at the necks of my 223 cases. If the neck tension was in fact 0.00167” or 1.67 thousands as we like to say, a variation of the same 0.00072” means now that there is a 43% variation in neck tension. It also means that some necks could have a high neck tension of 0.00203” or 2.0 thousands or a low neck tension of 0.00131” or 1.3 thousands. Now I would challenge anyone on this board to tell me that two cases, one with 2.0 thousands tension and one with 1.3 thousands tension would have the same MV?

Surprised? Why? After all were only talking about number like 0.00072”? This to me is more like "Picking Dog Poop out of the Pepper". 8)

 

[amlevin]

Now, let’s look at the necks of my 223 cases. If the neck tension was in fact 0.00167” or 1.67 thousands as we like to say, a variation of the same 0.00072” means now that there is a 43% variation in neck tension.

So it's 43% but what does that actually translate into when using units of pressure?

If you're enamored by "numbers" OK, it's a large number. If performance on the target is more important, the point of diminishing return was reached long ago. Just how many PSI of pressure variation behind the bullet does that "1.67 thousandths" actually amount to when a round develops close to 60,000 psi to begin with?

I can't wait until the day I see someone arrive at the range with a fully instrumented barrel and only fires a shot when the barrel temp is exactly the same as after the last fouling shot, Where he mic's the barrel to make sure it hasn't larger in diameter than with a previous shot.

As for accuracy???? I'd put more effort into developing my skills rather than trying to harvest feces from the black spice. 8) 8)

 

[jlow]

Now, let’s look at the necks of my 223 cases. If the neck tension was in fact 0.00167” or 1.67 thousands as we like to say, a variation of the same 0.00072” means now that there is a 43% variation in neck tension.

So it's 43% but what does that actually translate into when using units of pressure?

If you're enamored by "numbers" OK, it's a large number. If performance on the target is more important, the point of diminishing return was reached long ago. Just how many PSI of pressure variation behind the bullet does that "1.67 thousandths" actually amount to when a round develops close to 60,000 psi to begin with?

I can't wait until the day I see someone arrive at the range with a fully instrumented barrel and only fires a shot when the barrel temp is exactly the same as after the last fouling shot, Where he mic's the barrel to make sure it hasn't larger in diameter than with a previous shot.

As for accuracy???? I'd put more effort into developing my skills rather than trying to harvest feces from the black spice. 8) 8)

It’s not love or hate so enamored has nothing to do with this.

To me 43% difference is just a pretty significant number. I have frankly no idea what this does to MV, PSI of pressure variation. I honestly wish I did but all I am saying is this is a pretty big number and at least to me when I am trouble shooting, I learned not to dismiss these things (like you are doing right now) unless I know it is not going to make a difference. You don’t make any headways when you do this.

I guess I don’t understand why you feel you have to dismiss this observation without some clear foundation or evidence that it means nothing. I don’t dismiss it because I don’t know. If you know for sure it means nothing then I wish you would share with us your understanding.

 

[37Lincoln1]

I'm loving this whole discussion.

jlow you have some patience and really go after it, good for you! I'll probably never get there, I don't know if that is a good or bad thing. . .

What I gather amlevin is saying, put in layman's terms, is that there comes a time when we have refined the rifle and its projectiles to the point that the weak link is the nut behind the trigger. How do we measure that? ;D

 

[jlow]

I'm loving this whole discussion.

jlow you have some patience and really go after it, good for you! I'll probably never get there, I don't know if that is a good or bad thing. . .

What I gather amlevin is saying, put in layman's terms, is that there comes a time when we have refined the rifle and its projectiles to the point that the weak link is the nut behind the trigger. How do we measure that? ;D

Thanks! Appreciate you input.

I understand the sentiment regarding the shooter being the weakest link and its certainly true for me, but unfortunately my reloading is also nowhere close to where I can say it’s even close to be good enough to move on, so it's back to the basics for me!

 

[LHSmith]

jlow......You can continue your quest to produce the most perfect ammo ever made in recorded history , but the bigger picture lies in learning how to tune a load for a given match and make adjustments throughout the day, becoming proficient at reading range conditions, and acquiring the proper rifle handling skills to get shots down range timely and with minimal upset to your rest set-up.
Spend your time figuring out how to address the load as powder density changes from hour to hour.
Sorry, but your affinity with % deviation is plain silly.
The bottom line at the end of the day, is who produced the best group and/or score aggregate.....There is NO awards for who had the lowest SD. or most consistent chamber pressure, or most consistent neck tension.
This is my last post on this thread.

 

[jlow]

The thing that bothers me about the response on the board is some people appears to assume that they know that you already have a good enough load for 1K or 600 yards and all you are doing is blowing smoke and wasting time. Does anyone think that it is a bit assuming that they know what level my reloading is?

I come to this board because I want to learn to improve on my reloading skills. We are all adults and so the assumption is we can make decisions as to what is good for ourselves – its’ a free country right? If you are willing to help, please speak up. If you think I am making a mistake you can speak up to but keep in mind that between the two of us, since I have all the information regarding where my reloading is, there is a reasonable chance that I know a little bit more about how good and how poor my reloading is even though you may know more about reloading in general than me. Please keep this in mind before you post and insist that I am wasting my time.

It is just good manners.

 

[DanConzo]

jlow--Don't worry about discussions, just like the one guy said the end result is what counts. Heck we didn't even get into priming, checking and altering bullets, chamfering case mouths, deburring flashholes, web thickness, primer pockets, powder handling and then to the shooting techniques (bags, rests, free recoil, cheek weld if any, lightning triggers, grease lightning locktime, firing pin protrusion and fall distance and probably many more I forgot. Heck we can go all winter. One thing though you can shoot well once but being able to repeat it again and again is difficult, I guess that is why we are on this site.

 

[jlow]

DanConzo – appreciate your comments, but really looking back at all the discussions in the last few days, it appears that all we are doing is trading subjective comments and despite my hopes for help, it is clear that it’s not going to happen. Instead of burning a lot more time getting people even more frustrated, I am just going to hang it up.

It’s too bad since I have high regards for this board but I realize that good things don’t happen all the time.

 

[LongRanger]

Well. If all the back and forth about measurements is over I'd like to get back to BENCH.

BENCH....without changing anything (bullets/powder/charge/seating depth/anything) make up at least 15-20 reloads out of each of your three sizer dies. Shoot them in sets of 5 shots, hopefully over a chronograph, at a target at least 200, preferably 300, yards away. Your rifle will tell you which die it likes best. Then you will ready to start working out the most accurate load you and your equipment can deliver.

And remember....all brass is born female and, being female, everything you do to it has a consequence and often reacts differently the next time you do the same thing to it.

Frank B.

 

[Nomad47]

And remember....all brass is born female and, being female, everything you do to it has a consequence and often reacts differently the next time you do the same thing to it.

Frank B.

Now THAT is funny. I never looked at it that way - but it is a fact.

 

[nosualc]

jlow,

I appreciate your efforts and your application of the scientific method. I too come from a detail oriented profession and often go deeper on my reloading techniques than my friends would believe necessary.

What I would like to know is if the focus on neck tension (to the degree that you have) actually makes a significant/repeatable (positive) difference on the target, for that is the goal of the exercise is it not?

Rifle shooting is a complex system, and many of the variables are beyond our means to measure, or measure directly. Hyper fine control on one variable will eventually be lost in the noise of the uncertainty in the others. Measuring neck thickness to infer tension is an example. It works as a rough measurement because there is correlation, but that are many unknowns that will eventually introduce more variability than you can control.

From my own experience, I expect you are well into the territory of diminishing returns. If you are not, I would be the first one to admit your greatness and mimic your techniques! Either way, the efforts advance our sport, thankyou for sharing your work.

When I started all this a great shooter and mentor told me, "You engineers think too damned much. Go out and shoot 1000rds". He was right.

-nosualc

ps - bench, sorry for the continued thread hi-jack. IMO, the best thing you can do is get a Redding FL bushing die and 2-3 bushings. Change the bushings and keep everything else the same, and let your rifle tell you what it likes.

 

[jlow]

Nosualc – thanks for your kind words.

In terms of neck tension, I am no expert but from what I have read and personally experience, neck tension is one of the more important characteristics when it comes to obtaining repeatable MV. This is most important when you are shooting long distance since slight variations in MV will show up as vertical stringing.

I think if my goal was only to cut very reproducible neck thickness then I would certainly agree that I am likely in the territory of diminishing returns. But as it is, that was not my goal, my goal was to make the necks reproducible enough so that I can unmask other variables which might be causing my problems in MV variability.

As it was, I happened to end up being able to turn necks with very low variability. You got to understand that in this sport, you frequently have a goal but what comes out from your efforts are frequently unpredictable. I never set a goal to say cut necks to say 0.0002” variability, what I did was to try to do my best and see if it was good enough. As it turns out, it was very good and I am glad to have it. However, it is now time to use it to figure out my real problem.

I think this last part is what people appears to have difficulty understanding.