It seems to prove your point you are wanting to use a different set of case prepping rules for measuring volume vs weighing.
brass weight sorting
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Mikecr
Well-Known Member
Edd, not really sure what you mean.
For brass preps I :
Cull brass by thickness & thickness variance
Turn necks (and initial trim if needed)
Uniform primer pockets & flash holes
Fireform w/3 loads while finding best seating distance to lands (and neck sizing only)
Final trim to length
Cull by H20 capacity
Bump to HS at -1thou
For brass preps I :
Cull brass by thickness & thickness variance
Turn necks (and initial trim if needed)
Uniform primer pockets & flash holes
Fireform w/3 loads while finding best seating distance to lands (and neck sizing only)
Final trim to length
Cull by H20 capacity
Bump to HS at -1thou
If you use that same prep procedure down to the cull by H2O and instead cull by weight, how much difference will there be in your case lots?
milanuk
Well-Known Member
Mikecr,
Lets just say for the sake of argument that I'm game to try your way of sorting by volume, at least as an experiment at some point this winter to while away the time.
Lets also say I have a brand new barrel being fitted and due back from the gunsmith sometime in the next week or two. .308 Winchester Brux 30" fluted heavy Palma 1-12" tw '95 Palma chamber. I've also got a bunch of new Lapua Palma brass that needs fire-formed in this barrel, and a whole bunch of Sierra 155 MK Palma (2156) bullets and Berger 155.5 BT Fullbore bullets. I've got a lab-grade scale (Sartorious GD-503), several concentricity gauges, good dies, good press(es), and generally know how to use them. My chronograph is reasonably decent - a CED Millennium, and I could probably arrange for use of an Oehler 35P if I ask nicely.
I can do the testing on each case of say, 50 pcs and record the data in a spreadsheet so people who want can go over the numbers as obtained by a somewhat impartial third party (me) who doesn't really have a dog in this fight. I have done some limited testing in the past regarding weight vs. volume and found there to be a slight correlation - enough to be 'significant' for statistical purposes at least. That earlier test had some aspects that I'd like to revisit, so thats why I'm considering doing this again.
Can you describe for me in detail (email me if you don't want to go into it here) your process for sorting cases, specifically what you do to get consistent readings when measuring water volume of cases?
Monte
Lets just say for the sake of argument that I'm game to try your way of sorting by volume, at least as an experiment at some point this winter to while away the time.
Lets also say I have a brand new barrel being fitted and due back from the gunsmith sometime in the next week or two. .308 Winchester Brux 30" fluted heavy Palma 1-12" tw '95 Palma chamber. I've also got a bunch of new Lapua Palma brass that needs fire-formed in this barrel, and a whole bunch of Sierra 155 MK Palma (2156) bullets and Berger 155.5 BT Fullbore bullets. I've got a lab-grade scale (Sartorious GD-503), several concentricity gauges, good dies, good press(es), and generally know how to use them. My chronograph is reasonably decent - a CED Millennium, and I could probably arrange for use of an Oehler 35P if I ask nicely.
I can do the testing on each case of say, 50 pcs and record the data in a spreadsheet so people who want can go over the numbers as obtained by a somewhat impartial third party (me) who doesn't really have a dog in this fight. I have done some limited testing in the past regarding weight vs. volume and found there to be a slight correlation - enough to be 'significant' for statistical purposes at least. That earlier test had some aspects that I'd like to revisit, so thats why I'm considering doing this again.
Can you describe for me in detail (email me if you don't want to go into it here) your process for sorting cases, specifically what you do to get consistent readings when measuring water volume of cases?
Monte
Good idea. If you can use a good machine rest using 3 points for holding the rifle, you'll eliminate the 5 to 20 fps muzzle velocity errors caused when us humans hold the rifle to our shoulder and shoot it. I've seen as much as 80 fps difference in average muzzle velocity between 2 people using the same ammo in the same rifle shot from the shoulder as it rests atop bags on a bench top. If you shoot the rifle slung up in the prone position, the chronograph results will probably be more accurate.
Mikecr
Well-Known Member
Edd, I don't know as I haven't done this as a weight-vs-capacity experiment using any scientific method. That would be a bigger endeavor than it seems I'm sure.
I have observed weight of cases followed by capacity measure and found that it's often an abstract correlation.
3 things I find:
Cases weighing the same having different capacity
Cases weighing differently but having the same capacity
Cases in some brass lots showing a direct and predictable relationship, while other brass lots for the same cartridge were not so kind.
With this, I don't recognize weight measure as an 'alternative' to capacity measure(any more than I would recognize culver clicks as an alternative to powder measure).. It would be sweet if I could, but it's too late. I already know this assumption is wrong, and any bad shots downstream of it would just bring it back to suspicion.
I've heard of BR shooters tossing brass on flyers, and I suspect this and other common shortcuts combine to lead them to it.
You could do that.
I take each fired-unsized case, deprime it(with a hand decapper) and stand it on a plastic golf tee on a scale(the tee is inserted consistently into the flash hole). Then I zero the scale, and eyedrop water into the case until full to case mouth. Then I touch the meniscus with a tissue corner to flatten it flush with the case mouth and record the H20 capacity. I usually have a cup of water on the side with a few drops of alcohol in it to reduce water tension.
I typically lose ~10-15% of my cases(Lapua, Norma, Win) to measured capacity variance. I lost over half to thickness & thickness variance well before this..
That's not bad for me though because brass is cheaper than my efforts, and my remaining cases will outlast many barrels.
They are truly matched, and straight, and I can scratch these factors off the list.
I don't full length size cases –ever.
If you do then there is likely less gain in this as your capacities could change with every cycle. This would of course be a detriment to capacity specific testing. And then you could only match capacities before any FL sizing, for a baseline.
If that sucks, well then you could just match cases by weight, and no matter how you size them or how they perform, they will always weigh the same(if that makes ya feel better)..
I've also heard it said that cases continue to grow(beyond fireformed baseline) –if you don't FL size. Well I'm telling you that is only true when you cause it to be so.
I don't have this issue, and will never run into it.
I could check my cases with 30+ reloads on them today, and they would measure EXACTLY the same as I set way back.
This is because I matched them to begin with, and I avoid poor cartridge designs, extreme pressures, and over-sizing.
I do have to bump 30-35deg shoulders, but that's as sad as I accept right there.
I limit my pressures to 57Kpsi per QuickLoad (regardless of SAAMI max) because so far I measure brass yield beyond that.
I choose a capacity that gives me what I need from my bullets without destroying matched brass.
As far as competition and competitive performance, you better do what you have to do is my guess. I don't compete.
I know extreme pressures can be used to work around deficiencies in ammo, as proven over & over with 6PPCs/30brs at short range. But it appears to me that 'consistent' 1/2moa of accuracy is beyond even winning 1kyd shooters. And I don't see a need to work around anything for 1/2moa, or even 1/4moa of accuracy.
From any angle, I don't see where matching capacity would hurt competitive performance.
I have observed weight of cases followed by capacity measure and found that it's often an abstract correlation.
3 things I find:
Cases weighing the same having different capacity
Cases weighing differently but having the same capacity
Cases in some brass lots showing a direct and predictable relationship, while other brass lots for the same cartridge were not so kind.
With this, I don't recognize weight measure as an 'alternative' to capacity measure(any more than I would recognize culver clicks as an alternative to powder measure).. It would be sweet if I could, but it's too late. I already know this assumption is wrong, and any bad shots downstream of it would just bring it back to suspicion.
I've heard of BR shooters tossing brass on flyers, and I suspect this and other common shortcuts combine to lead them to it.
You could do that.
I take each fired-unsized case, deprime it(with a hand decapper) and stand it on a plastic golf tee on a scale(the tee is inserted consistently into the flash hole). Then I zero the scale, and eyedrop water into the case until full to case mouth. Then I touch the meniscus with a tissue corner to flatten it flush with the case mouth and record the H20 capacity. I usually have a cup of water on the side with a few drops of alcohol in it to reduce water tension.
I typically lose ~10-15% of my cases(Lapua, Norma, Win) to measured capacity variance. I lost over half to thickness & thickness variance well before this..
That's not bad for me though because brass is cheaper than my efforts, and my remaining cases will outlast many barrels.
They are truly matched, and straight, and I can scratch these factors off the list.
I don't full length size cases –ever.
If you do then there is likely less gain in this as your capacities could change with every cycle. This would of course be a detriment to capacity specific testing. And then you could only match capacities before any FL sizing, for a baseline.
If that sucks, well then you could just match cases by weight, and no matter how you size them or how they perform, they will always weigh the same(if that makes ya feel better)..
I've also heard it said that cases continue to grow(beyond fireformed baseline) –if you don't FL size. Well I'm telling you that is only true when you cause it to be so.
I don't have this issue, and will never run into it.
I could check my cases with 30+ reloads on them today, and they would measure EXACTLY the same as I set way back.
This is because I matched them to begin with, and I avoid poor cartridge designs, extreme pressures, and over-sizing.
I do have to bump 30-35deg shoulders, but that's as sad as I accept right there.
I limit my pressures to 57Kpsi per QuickLoad (regardless of SAAMI max) because so far I measure brass yield beyond that.
I choose a capacity that gives me what I need from my bullets without destroying matched brass.
As far as competition and competitive performance, you better do what you have to do is my guess. I don't compete.
I know extreme pressures can be used to work around deficiencies in ammo, as proven over & over with 6PPCs/30brs at short range. But it appears to me that 'consistent' 1/2moa of accuracy is beyond even winning 1kyd shooters. And I don't see a need to work around anything for 1/2moa, or even 1/4moa of accuracy.
From any angle, I don't see where matching capacity would hurt competitive performance.
If you do get together some numbers I will runs some stats for you. Start with pm'ing me the weight and H20 capacities, then we can see if your chrony data is useable. These conclusions as mike eluded to are only relevant for this lot of brass, but useful and interesting. Powder compression also likely will change velocities, and chronies can be pretty fickle, but give it a go. I'm in. Number all 50 cases and load them all the same regardless of weight or capacity (after recording the data). Shoot a couple of warm up shots to warm the barrel, then shoot your 50 rounds, one shot every 2-3 minutes exactly and record velocity.
Buffalobob
Well-Known Member
I sort brass by weight and then again by range results. Some brands and calibers of brass and bullets I don't bother to sort.
So somehow I always seem to be in a position of needing to give away a lot of elk and antelope meat.
So somehow I always seem to be in a position of needing to give away a lot of elk and antelope meat.
milanuk
Well-Known Member
Like I mentioned earlier, this will likely be an all winter project for me, between getting the gun back, getting a known good load working in this gun, etc.
One of the things I want to do for this one is construct a 'box' for my chrono, so that the screens are essentially inside a tube to where external lighting levels and angles won't skew the reads. Even with IR screens I've seen some screwy results on days with steep light angles, etc. The two main problems I had last time I messed around with this kind of experiment (actually for my final paper in my intro stats class
) was the gun position moving to the side causing a couple shots to have errant MV as they weren't quite shooting thru the same 'window', and with the length of time involved (3 minutes per shot) you're looking at over 2-1/2 hours for a complete session - lots can happen to the ambient light levels (like clouds) in that time. Hopefully by using IR lighting inside the box (so its effectively the *only* lighting) I can alleviate some of that. I'll also probably be using a front rest and rear bag (or a machine rest if I can find one) to make the position as close to 100% repeatable as possible.As it turns out, I mis-spoke on the brass. I've already weight sorted all my current batch of brass so I'll grab another box of regular Lapua (not Palma/ small primer) brass for this test - its not like I won't have a use for it afterwards
I'll set aside 50 for the test, and use the other 50 for initial load development. I have a set of Wilson dies - a stainless neck die and a stainless micrometer seater die, so that should satisfy Mike's caveat about neck sizing only. Generally I F/L size for a very slight (0.001", +/- 0.0005) bump but I can do it either way for this project.Also... as I have an ultrasonic cleaner, I can fairly easily de-aerate the water used for filling the cases by putting the container in the tank for say 10 minutes.
Questions:
Do we care about water volume of the virgin (unfired) brass? Do we only want to take this measurement on 1x fired cases? Do we want to take it again on 2x fired cases? Given the tedium of the process involved, I'm leaning towards option B (1x only)...
Do we want the cases cleaned in between firings in any particular way? I have the setups for anything between a quick twist of the neck with #0000 steel wool, to ultrasonic to wet tumbling with stainless pins. The latter probably gets them cleanest, but we'd lose the ability to tell which case was which when they came out. With US you could put them in a rack and keep track of them fairly easily. Does it even matter that they are cleaned down to 'bare metal' for the volume test?
Do we want/need to establish a level of error or uncertainty for the volume measuring process i.e. how consistent/repeatable is it really since we are having to rely to some degree on an 'eyeball' evaluation of the meniscus at the case mouth? Is it something where to do it 'right' we need to take multiple readings (just shoot me now...) on each case and average them?
How far down the rabbit hole do we want to go?
Monte
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Monte
2 more cavaeats for discussion
1. According to MikeCR he does not FL size, yet he has posted previously that he routinely uses a fitted/honed body bump die and a NS die.
So are we really talking about just not using a (one step) FL size die and instead using a NS die and body bump die and in reality FL sizing in two steps but calling it NS'ing. That is still FL sizing in my books, only two steps. So what are you going to test?
2. If the test is to use the MikeCR parameters, then 57K PSI (from QL data) is the max working limit accordingly, which is in many guns is not close to max, ergo it is easy to see why not case expansion. However, that is not the norm for big capacity cartridges and most LR hunters I am sure.
You and I both know that German Salazar has tested primers over an Oehler 43 with strain guages and shown over a 5000 PSI difference in same loads except primers as posted on his site. How do you factor 5k variance in PSI working loads in? QL does not consider primer variances in their data amongst many other things.
Plus I am confused with first measuring thickness and throwing cases out and THEN measuring H2O capacity. What is the value of throwing cases out to thickness first instead of H2O measuring capacity, IF it is the meaningful measurement claimed. If capacity is THE factor, then thickness has zero effect if capacity is the same it would seem!
BTW, the IBS 1000 yard light gun record for 10 separate matches,(different days and 5 shot groups) was 5.3 inches. That was broke this year and I do not have the new number. The heavy gun 10 match agg (10 shots) was 5.9 inches and was also. 6 match aggs for both are in the 4 inch range, which is under .5 MOA. A bunch of 2-3 inch groups were shot at the Nationals in Sept. No one here shoots 5 or 10 shot groups and quotes MOA except the few 1k and Fclass guys who have to test to those parameters.
Anyway, going to follow this and see what you find. I know what I found out years ago doing trying it.
John Hoover and his family in PA has won and broke more records by chrono'ing each piece of brass and sorting that way. I tried that too and got too much repeated variance using an Oehler 35 with 3 screens over 8 foot bars. That is way more precise than the standard run of the mill chrono but still not up to a 43's accuracy.
I and most others have found that sorting to 1 grain (WSM size case) is more than enough with neck turning.
Uniform neck tension is the most critical element most 1k shooters have found. We have tried sorting by pin guage measurements of the necks, etc and it still comes to FL sizing, annealing and monitoring seating pressure when seating the bullets.
If you really want to get anal, get a very good electronic scale and weigh primers. That has been tried too!
2 more cavaeats for discussion
1. According to MikeCR he does not FL size, yet he has posted previously that he routinely uses a fitted/honed body bump die and a NS die.
So are we really talking about just not using a (one step) FL size die and instead using a NS die and body bump die and in reality FL sizing in two steps but calling it NS'ing. That is still FL sizing in my books, only two steps. So what are you going to test?
2. If the test is to use the MikeCR parameters, then 57K PSI (from QL data) is the max working limit accordingly, which is in many guns is not close to max, ergo it is easy to see why not case expansion. However, that is not the norm for big capacity cartridges and most LR hunters I am sure.
You and I both know that German Salazar has tested primers over an Oehler 43 with strain guages and shown over a 5000 PSI difference in same loads except primers as posted on his site. How do you factor 5k variance in PSI working loads in? QL does not consider primer variances in their data amongst many other things.
Plus I am confused with first measuring thickness and throwing cases out and THEN measuring H2O capacity. What is the value of throwing cases out to thickness first instead of H2O measuring capacity, IF it is the meaningful measurement claimed. If capacity is THE factor, then thickness has zero effect if capacity is the same it would seem!
BTW, the IBS 1000 yard light gun record for 10 separate matches,(different days and 5 shot groups) was 5.3 inches. That was broke this year and I do not have the new number. The heavy gun 10 match agg (10 shots) was 5.9 inches and was also. 6 match aggs for both are in the 4 inch range, which is under .5 MOA. A bunch of 2-3 inch groups were shot at the Nationals in Sept. No one here shoots 5 or 10 shot groups and quotes MOA except the few 1k and Fclass guys who have to test to those parameters.
Anyway, going to follow this and see what you find. I know what I found out years ago doing trying it.
John Hoover and his family in PA has won and broke more records by chrono'ing each piece of brass and sorting that way. I tried that too and got too much repeated variance using an Oehler 35 with 3 screens over 8 foot bars. That is way more precise than the standard run of the mill chrono but still not up to a 43's accuracy.
I and most others have found that sorting to 1 grain (WSM size case) is more than enough with neck turning.
Uniform neck tension is the most critical element most 1k shooters have found. We have tried sorting by pin guage measurements of the necks, etc and it still comes to FL sizing, annealing and monitoring seating pressure when seating the bullets.
If you really want to get anal, get a very good electronic scale and weigh primers. That has been tried too!
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milanuk
Well-Known Member
Well, I have straight-up Wilson neck dies, I have Lee Collet dies, I have Redding Type 'S' F/L bushing dies (that I use probably the most), and I have a Forster Precision Bump die (sizes neck and bumps the shoulder, but nominally doesn't touch the shoulder) that I've started playing with recently. Pick yer poison...
Yeah... 57k likely ain't gonna cut it here neither. Palma / F-TR loads using 155s tend to run on the warm side, for sure.
Primers are one of those nasty 'black box' components that for the most part we don't understand as well as we'd like, and can't do much about if we did.
I'm going to go out on a limb and guess the (perceived) value is in culling cases with un-even case wall thickness which could lead to the proverbial 'banana shaped' cases with one portion expanding/stretching at a different rate than the rest of the body. It would be done separately because it has no real bearing on case volume in and of itself, and there would be no point in measuring the volume on cases already rejected for other reasons.
I've seen some folks try measuring insertion/extraction force with pin gauges... seems like they are struggling to get a) consistent results and b) correlate those measurements with results on target. I know the force measurment system on my K&M arbor press seemed like a wonderful idea... but I've yet to be able to tell any meaningful difference on target from it that I couldn't already have deduced by 'feel' while seating.
I seem to recall people thought a significant portion of the variation in primer weight had to do with how much of that colored 'goop' the manufacturer globs on there
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I totally agree with paragraphs 1 and 2.
A friend tested primers years ago by threading a BB gun barrel into a .17 Rem. shot out barrel right in front of the case mouth. Cases' primer pockets were reamed out to hold large rifle primers and flash holes drilled out to the correct size of about .045 thousandths. He shot BB's stuffed in .17 Rem. case mouths and recorded their velocity through a chornograph. Primers producing the lowest velocity shot the most accurate in both .308 Win. and .30-.338 Win. Mag rifles. The best primers for accuracy did not always have the lowest spread in velocity; some shot BB's pretty fast with low velocity spreads but those hotter ones played hell and high water with accuracy.
Another guy I know weighed primers before seating, recorded the weight to the hundredth of a grain on the case then weighed them again after firing them. The difference in weight was what he thought the primer mixture and seal weighed. He didn't see any correlation between uniform primer mix/seal weight and best accuracy.
Some folks believe the man stirring the priming mixture slurry into a homogenous puddle then smearing it into the holes in the pelleting plate is the key to uniformity. This is oft times been called the "black magic" process in the ammunition industry.
milanuk
Well-Known Member
Well, the gun is still off at the gunsmith's, and he's off hunting in Montana, the lucky dog
Got the brass in today... picked 50 out and weighed 'em as they came out of the box. Scale used is a Sartorius GD-503 analytical balance, with readability to 0.005gn
After that I ran them over a K&M expander mandrel as per my usual with virgin Lapua brass, as in my experience the necks are too tight plus with the new blue box stuff the necks are a little dinged up and need rounded out.
Next step was to measure OAL so I now what minimum OAL to trim to. Measuring was done with a Mitutuoyo Digimatic 6" digital caliper, reads to 0.0005".
Over the next few days I will be doing the trim/chamfer/deburr stuff, and checking the case wall runout and neck thickness runout - not necessarily germane to this particular test, but information I want for other reasons.
Currently inputting the data into a spreadsheet on Google Docs (which should be available from this link here) so that others can see the raw numbers and download the data for themselves.
What other measurements do we want done on the virgin cases? Speak now or forever hold yer peace...
Got the brass in today... picked 50 out and weighed 'em as they came out of the box. Scale used is a Sartorius GD-503 analytical balance, with readability to 0.005gn
After that I ran them over a K&M expander mandrel as per my usual with virgin Lapua brass, as in my experience the necks are too tight plus with the new blue box stuff the necks are a little dinged up and need rounded out.
Next step was to measure OAL so I now what minimum OAL to trim to. Measuring was done with a Mitutuoyo Digimatic 6" digital caliper, reads to 0.0005".
Over the next few days I will be doing the trim/chamfer/deburr stuff, and checking the case wall runout and neck thickness runout - not necessarily germane to this particular test, but information I want for other reasons.
Currently inputting the data into a spreadsheet on Google Docs (which should be available from this link here) so that others can see the raw numbers and download the data for themselves.
What other measurements do we want done on the virgin cases? Speak now or forever hold yer peace...
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Buffalobob
Well-Known Member
You should have started with Winchester or Nosler brass so you would get variations significant enough to have an observable outcome.
