Concentricity , what seater die should I get ?

[Unclenick]

Well, strictly speaking, you can, in fact, calculate tensile stress around the neck from a combination of the change in cross-sectional area of the neck due to the measured expansion of the neck OD over the bullet and the change in neck wall thickness it causes using the modulus of elasticity (16,000,000 psi for 70:30 cartridge brass) and Poisson's ratio (0.375 for 70:30 brass). Once you have that, you can work backward through the hoop stress calculation to find the pressure applied inward against the neck. When you multiply that times the contact area between the neck and bullet and by the static coefficient of friction between gilding metal and cartridge brass, the area will have canceled out and you would have bullet pull in pounds.

However, that is all in theory and not of much practical value because of all the places it can go wrong. Your case alloy probably isn't exactly 70:30 brass. Your bullet maker may use a slightly different gilding metal alloy than average. Your coefficient of friction probably won't match perfectly from case-to-case due to neck lube or the presence of carbon or how smooth the surface is. SS pin cleaning might fix the coefficient of friction variation, but even so, that number would only be good for a while, as brass and gilding metal tend to begin to stick together over time.

So, bottom line, yes, tension in psi can be calculated and bullet pull calculated from the result, but why the dickens would you bother when measuring bullet pull directly would be so much easier and gets around the alloy and other variables?

Originally Posted by cw308

What I'm getting from your post , you run a case up into the die , raise the stem and expander untill you feel contact with the bottom of the case neck . Correct? ...

That will be too snug. The brass can't really turn the corner as quickly as that would demand, so it would just jam on the upstroke. The idea is just to have the bottom of the neck engage the expander before the case mouth leaves the die. This is to get the neck started straight over the expander and without sideways pull. The position of the expander can be determined by turning the stem up until it contacts the brass at the neck/shoulder junction, as you described, and then turning it back down from that point by a distance equal to about 2/3 to 3/4 of the length of the case neck. The proportions of necks are so variable I can't give you an exact amount. With some of the WSM cases, it might not work at all. But basically, the closer you can get the expander to the neck portion of the die without feeling it start to increase your resizing or withdrawing effort, the better alignment with the expander should be imposed by it.

I can see situations in which the above may not work well due to poor die and press alignment or uneven drag on the expander due to uneven lubricity or neck wall thickness pushing the expander to the side and letting it shift alignment after the neck mouth clears the die. You'll have to experiment a bit to get the most out of it.


Hounddawg,

If he pushed the die until it popped the aluminum plug, I think the problem he had was the mandrel being a little wide. Lee makes them only about 0.001"-0.002" under bullet OD, and if you get one on the larger size of the tolerance range or a bullet on the narrower side, and especially if your brass needs annealing to take the spring out of the neck, you can end up needing a narrower mandrel than the die came with. A number of users report having to reduce them 0.001".

[F. Guffey]

So, bottom line, yes, tension in psi can be calculated but why the dickens would you bother when measuring bullet pull would be so much easier?

Why bother? Reloaders have purchased the Hydraulic seating press with the pressure gage, some posted the results in real time on the Internet. Not a problem for me but with all of their efforts for precision they found as much as 30 pounds of difference when measuring the effort required to seat bullets in cases that were believed to be sized with the greatest care.

why the dickens would you bother when measuring bullet pull would be so much easier?[/

This is about the infatuation reloaders have with tensions and thinking they can measure tensions. I have strain gages, tension gages and deflection gages. It can not be any easier to measure the amount of effort required to seat a bullet than to measure the effort in pounds.

I remember the member that spent time at the Aberdeen test facility; he had bullet hold that he claimed to be measured ay 600 pounds, after that we went into the cold weld time period.

Pulling and seating? To understand that these members require a picture, and then there is that something that is missing. They can not say OIC, or 'I understand now' or 'I have never looked at it that way'.

When using a bath room scale there is no difference between pulling and or pushing. I understand, they have to get 47 firings out of each case; not me! because I am not the one with the problem; I am the fan of bullet hold, I want all the bullet hold I can get.

To push a bullet out of the case drill the primer pocket/flash hole out to a diameter that will accommodate a dowel/cleaning rod then turn the case upside down and support the case at the shoulder. After turning the case over and supporting the case at the shoulder push the bullet out and at the same time read the scale.

And yes a case neck that has been annealed will skew the results when the reloader goes for neck tension, he can not screw the results up if he is going for pounds. Correction: I can't screw it up but I am not the one that makes this stuff up.

F. Guffey

[hounddawg]

As UncleNick pointed out if you know the elasticity of the metal it is just a matter of math. For the ultimate precision we used micrometers to measure thread stretch to ensure bolts were properly torqued on certain pieces of gear.

Much easier just to take two measurements with a set of calipers and use 1st grade math. If it works for world class shooters like Litz, Boyer and Holland it is good enough for my shooting

late edit - only real test is at the shooting bench. If Your method is working for you then have at it. If it is not try changing something out or trying something different. I am pretty much at peace with my reloading and my gear now my reloads work and my gear is adequate. What I need now more shooting bench experience to learn how to properly shoot them

[cw308]

Unclenick
Thank you for getting back . I understand exactly what your saying , I will give it a try . Always willing to try something new . I have the stem and expander hight as if the pin was installed , my runout is good . I do remember when using the Redding bushing dies the ball was in the higher position then the standard die . Thanks again.

Chris

[LE-28]

I am the only reloader on any reloading forum that has tension gages. My tension gages do not convert to thousandths, my tension gages are calibrated to pounds,

tensin gauge.jpg


This is my tension gauge. It measure in pounds and is NIST tracable with certs.

You are not even close to being the only reloader on any forum that uses strain/tension gauges.


But I don't know if I remember how to upload a pic on these forums.
I'll have to see when I post this.

Well it's sideways but it is here.

[Metal god]

What does tension anything have to do with what seating die I get and the runout they give ? Same old memember at his same old tricks . Trolling the other members in order to get a negative response . The ignorance it takes to even think one is the only one of anything speaks to mind set not conducive to reasonable conversation with others . He’s currently on at least three different threads here at TFL not speaking about anything in the OP derailing them as he always does . Has Guffey even recommended a seater die or suggested how to use the concentricity gauge in this thread ? Everyone else has and it is appreciated and I thank you all for your help .

I had hoped to do some testing of all the different seater dies and post the results in this thread . Not sure we'll ever get there , guess the troll wins again .

Troll

In Internet slang, a troll (/troʊl, trɒl/) is a person who starts quarrels or upsets people on the Internet to distract and sow discord by posting inflammatory and digressive, extraneous, or off-topic messages in an online community (such as a newsgroup, forum, chat room, or blog) with the intent of provoking readers

[hounddawg]

well personally I think it is time to put the trolls under the bridge and hit the ignore button. At least that is what I intend to do

[F. Guffey]

But I don't know if I remember how to upload a pic on these forums.
I'll have to see when I post this.

Well it's sideways but it is here.

Thank you for your effort, there is no way to get away from the 'it measures in pounds', thing. Back before the Internet reloading presses were tested, it is believed the 'C' press did not hold up but that did not apply to all of the 'C' type presses; some of the smaller 'C' presses were modified with a bar that made it an 'O' press.

And then they measured flex and deviation, some of the large presses with the column in the center did not hold up. All of the readings from the different gages read in pounds and or deviation, the deviation was measured in thousandths; the readings were useless until the strain was know and the strain was measured in pounds.

And then there was the press that received the worst rating. I was at the NAPPA Flea Market when I found a dealer selling restaurant supplies. One piece of equipment he identified as a 'juicer'. I knew what it was so I asked him how it worked. I finally convinced him it was a reloading press and it was not a good one. I purchased it for $10.00. The best way to describe it as it went through its paces was to say it looked like a spider doing push ups.

RCBS reinvented the 'column through the middle press', at first there were rave reviews and then suddenly? I can only guess they sold out.

F. Guffey

[F. Guffey]

Much easier just to take two measurements with a set of calipers and use 1st grade math. If it works for world class shooters like Litz, Boyer and Holland it is good enough for my shooting

I do not have a different standard for different members.

COW308 declared he had .004" neck tension; if there is any truth to what you say and this stuff is first grade math we are back to what I said years and years ago, COW308 can have crush fit or he can have interference fit but he can not convert tensions to pounds.

Much easier just to take two measurements with a set of calipers and use 1st grade math

So how does a 1st grade student convert .004" crush fit to tensions when the only gage available to him measures in pounds?

F. Guffey

[F. Guffey]

And now we are back to bullet hold, I am the fan of bullet hold, I want all of the bullet hold I can get and I did not invent and or discover bullet hold. Lyman did say crimping can be a bad habit.

F. Guffey

[hounddawg]

I had hoped to do some testing of all the different seater dies and post the results in this thread . Not sure we'll ever get there , guess the troll wins again .

Well I hope it continues ontrack myself. I will be opening a new box of Lapua next week and am giving serious consideration into doing a annealed vs unannealed 5 reload test with 20 of them

[F. Guffey]

Well I hope it continues ontrack myself. I will be opening a new box of Lapua next week and am giving serious consideration into doing a annealed vs unannealed 5 reload test with 20 of them

I would be interested if I thought he could be fair and objective nut experience tells me he has already got his mind made up before he starts. It has something to do with a man that claims he is a reloader and then claims he can not be convinced the case does not lock onto the chamber when fired.

Going to the range. It almost always has to do with something I built. I want to know what the rifle likes. I load 120 rounds of 12 different loads with 12 different case head stamps that include new, formed, once fired military and commercial cases. After tumbling I insist on getting the cases back in the same box they came from.

And I understand about variables, what I want is a small group, for 10 shots a group that is not larger than a quarter works without flyers. And then someone else has to determine what the rifle likes so I load another 120 rounds of 12 different loads, They are a different bunch, they fire one shot and then zero the scope; after zeroing the scope they shoot the next 10 rounds of that group. They are better shots than and get smaller groups.

Same thing with rifles I purchase; I purchased a 1905 303 Ross for $80.00, there was nothing I could do to improve on the accuracy but there is something about the in-line pull of the bolt that bothers me and it is an ugly rifle. Out of curiosity I dropped a brass rod down the muzzle. When the rod hit the bolt face, the bolt flew open. the tool I was using is a tool I use to check for bent barrels. Had the barrel been bent the rod would have slowed down and or stopped if it had been bent enough to see. I was impressed with the accuracy.

F. Guffey

[cw308]

hounddawg
Testing is good , will help everyone . With the seating dies , I've only tried the standard RCBS seating die and the Redding Competition Seating die which is more superior then the standard die . The Comp. Die is what I use kfor my 308 . Great Seating Die.

[cw308]

F.G.
How many times are we going to beat this dead dog to death ? What seating die do you use in center fire cases ? Hopefully there not home made .

[F. Guffey]

Hopefully there not home made .

Too late. I will tell you I never saw a tool seat a bullet straighter and with less effort. I do not have many weak moments but I almost had one when I finished that one. It was not that it was simple but reloaders would have a field day making insults.

Straight off the seater did not have a die body, and just for kicks I used a bottle capper instead of a press and then I used a bottle corker.
, I do not believe the presses qualified as in-line presses.

F. Guffey

[hounddawg]

@ CW like I say as long as it works don't mess with it. I am still not convinced seating dies really make a crap as far as concentricity and accuracy goes. I am using a .308 seating die to seat my .260's and getting very acceptable runout. I originally used it when I went from .308 to .260 figuring after barrel break in I would order a .260 seater but the .308 die worked so well I just kept on using it. Five years later if it works, don't mess with it. I do prefer the micrometer seating dies hands down and of the two brands I own I give the RCBS a nod over the Forster because of the bullet slot.

Getting .3 - .5 MOA accuracy with ammo seated with a seating die meant for bullets .04 diameter larger tells me that all that seater does is push the bullet down and the neck guides it in. I always like to do a light hand chamfer whether the case was trimmed or not, just to help the bullet get started and to prevent any jacket damage.

[cw308]

G.F
What seating die do you use for center fire.

[cw308]

hounddawg
I trim every time, it's more of a clean up then a trim because I trim every firing . I may go overboard because I'm only shooting 30 rounds every range trip . I chamfer inside an out even use a smaller caliber brush wrapped with 0000 steel wool chucked up in a drill press to smooth out any rough areas , seating is like butter .

[hounddawg]

sounds to me like you are doing everything right CW, I don't brush but just might start. Thinking about going the dry lube route again with fresh brass

[cw308]

hounddawg
I tried the Imperial dry lube that's added to those beads , I found if your shooting the reloads in a short period of time then you might not see any difference but if you aren't there is a bonding effect between the brass and the copper . From using the wool only and dry lube only the seating was just as smooth , even wool and lube it felt the same . That's using the standard die where I'm not adjusting neck tension .

[hounddawg]

I try to always load and shoot the same week maybe that is why I saw no improvement. Anyway I tossed my old .260 cases today the primer pockets are loosening and I am testing a pretty hot load.

I bought 200 Lapua a few months back when I caught a good sale and needed to bump my order up. There is no better time to test or retest some methods to see what effect they have

[cw308]

hounddawg
Lapua is top of the line , let me know how it works out . Nice talking to you . Be well.

Chris

[F. Guffey]

Hopefully there not home made .

Too late.

The seating die was of a different color, it does violated a rule or two when it comes to a seating die. But I have found nothing that does a better job of aligning the bullet with the case neck.

F. Guffey

[Metal god]

So I've not been testing a whole lot on the die or the concentricity gauge but did just buy this do-hicky
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Once it gets here I'll start doing some test on runout with three different types of sizing dies . Standard Redding , Redding type S bushing and Body only with Lee collet neck die after . With and with out expander button where applicable .


The Sinclair will check the outside concentricity of the necks while the new do-hicky should be able to check the inside neck concentricity .

It will take a little while to do all the testing but I'll likely start a new thread once completed . Any ideas as to order order or ways to run these test to ensure consistency and credibility of the end result ?

[Unclenick]

How much difference the seating die makes will depend in part on what other tools you have. The Redding Competition Seating Die I got in 30-06 back around the time they were introduced (1989 or 1990 or so) cut TIR down by a factor of 4 for me, as compared to the Redding standard seating die. But the press I was using for rifle loading then was not nearly as rigid or self-aligning as the Forster Co-ax press I usually use for precision rifle loading now.

So about all I can do by way of additional evidence for this is point you to the article by German Salazar comparing seating dies and showing actual targets with grouping improvement resulting from using the Redding Competition Seating die.