G'day all,
just another point to consider, to get that last 5% improvement is the time and effort worth it? That last 5% usually takes and enormous amount of resources to achieve even just a few % improvement that over 1000yds might not even be measurable in the short term as over time, barrel and cleaning wear will probably hide the improvement that may have been gained.
Is that time and effort better put to use refining existing practices as cheaper more practical option?
Is that time and effort better used to work some overtime to buy better reloading equipment or a better quality scope (you would be surprised at the mechanical errors in scopes)?
Is that time and effort better put on the mound in practice?
Remember, if you cant physically measure an improvement is the effort worth it? No scientist starts an experiment without a set goal and good prospects of results that can be analysed (good or bad).
You may be better in this case to carry a lucky rabbits foot while shooting........
Just a thought.
Cheerio Ned
Batching cases
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Barry Davies
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As an experiment that all can do -- take one case, prep it as you would normally do, load it, fire it and chronograph the speed. Do this several times within the hour.
Allowing for all the variables ( chrono also ) you will get some interesting results.
keep in mind that each time you fire it you have three variables that you cannot bring back and fire again -- Powder, projectile and primer. The only constant is the case.
Allowing for all the variables ( chrono also ) you will get some interesting results.
keep in mind that each time you fire it you have three variables that you cannot bring back and fire again -- Powder, projectile and primer. The only constant is the case.
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Tim L
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ned kelly wrote:G'day all,
just another point to consider, to get that last 5% improvement is the time and effort worth it? That last 5% usually takes and enormous amount of resources to achieve even just a few % improvement that over 1000yds might not even be measurable in the short term as over time, barrel and cleaning wear will probably hide the improvement that may have been gained.
Is that time and effort better put to use refining existing practices as cheaper more practical option?
Is that time and effort better used to work some overtime to buy better reloading equipment or a better quality scope (you would be surprised at the mechanical errors in scopes)?
Is that time and effort better put on the mound in practice?
Remember, if you cant physically measure an improvement is the effort worth it? No scientist starts an experiment without a set goal and good prospects of results that can be analysed (good or bad).
You may be better in this case to carry a lucky rabbits foot while shooting........
Just a thought.
Cheerio Ned
I take your point Ned, but a lot of this (for me) is doing what I can do rather than wishing I could do it (I don't actually drop test my flash holes btw, but I do batch them for weight). I get the gear I can afford, what I'm left with is time. Personally I think there are too many variables involved in shooting to do anything but measure the basics. From there on it's an interpretation of statistics which will be contaminated with a plethora of confounding variables, so even there it's more feel than definite results. I can't measure and confirm everything, so I simply adopt processes that I "think" might improve the consistency.
Its not so much whether the effort is worth it, as it is how many times I want to kick myself for not doing it. Alan took a days aggregate off me at Townsville,,,, by a point. I can't let that happen again now can I
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ned kelly
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G'day Tim,
I understand where you are coming from, as most of us have been in your shoes.
I must commend you for having the sense to ask as many just jump in and form habits or theories that may not be well based.
I think the best thing anyone can do is ask plenty of questions and keep asking even 20 years down the track.
My main point is to look at where you can make changes that get you to the 95% mark. Look for the big issues that you can control, that may be seating depth, change of primer or maybe bullet, sometimes, we flog a barrel only to find it is the barrel that is at fault; been there done that.
This is why I said what I said, as I do not think there is any solid proof in my mind that weighing cases works.
However, as is often the case if you THINK it does, then do it. Many of us do, when we lay down to shoot, we want ALL the little variables that we can control, ticked off the list so we can concentrate solely on shooting.
Also another point to consider is ensuring each case is trimmed to exactly the same length. Consider this, if one case is 10 thou longer than the shortest case and the bullet is normally seated 100 thou into the case, you automatically have a 10% variable. How does that effect ES & SD? This is probably more important than case weight.
On this point, I use a K&M tapered reamer ( https://www.kmshooting.com/catalog/new- ... m-338.html ) to deburr the case mouth. Regular deburrers leave a burr inside the mouth that can damage the bullet and change the case grip on the bullet. If you have a magnifier around 10x have a close look. Most optometrists can get them in (a 10x-20x Loupe see example http://www.amazon.com/Bausch-Lomb-Hasti ... YBHQ4156AN ) as used by jewellers. These are a vital tool to inspect cases, rifle muzzles etc for defects or issues.
These are some of the important but often overlooked issues that can cause more trouble than case weight.
Try to learn as much as you can on precision reloading from reputable sources or successful shooter in Long Range or BR shooting. Some very basic methods can reap amazing results.
Food for thought but if you think it is important then it IS IMPORTANT!
Cheerio Ned
I understand where you are coming from, as most of us have been in your shoes.
I must commend you for having the sense to ask as many just jump in and form habits or theories that may not be well based.
I think the best thing anyone can do is ask plenty of questions and keep asking even 20 years down the track.
My main point is to look at where you can make changes that get you to the 95% mark. Look for the big issues that you can control, that may be seating depth, change of primer or maybe bullet, sometimes, we flog a barrel only to find it is the barrel that is at fault; been there done that.
This is why I said what I said, as I do not think there is any solid proof in my mind that weighing cases works.
However, as is often the case if you THINK it does, then do it. Many of us do, when we lay down to shoot, we want ALL the little variables that we can control, ticked off the list so we can concentrate solely on shooting.
Also another point to consider is ensuring each case is trimmed to exactly the same length. Consider this, if one case is 10 thou longer than the shortest case and the bullet is normally seated 100 thou into the case, you automatically have a 10% variable. How does that effect ES & SD? This is probably more important than case weight.
On this point, I use a K&M tapered reamer ( https://www.kmshooting.com/catalog/new- ... m-338.html ) to deburr the case mouth. Regular deburrers leave a burr inside the mouth that can damage the bullet and change the case grip on the bullet. If you have a magnifier around 10x have a close look. Most optometrists can get them in (a 10x-20x Loupe see example http://www.amazon.com/Bausch-Lomb-Hasti ... YBHQ4156AN ) as used by jewellers. These are a vital tool to inspect cases, rifle muzzles etc for defects or issues.
These are some of the important but often overlooked issues that can cause more trouble than case weight.
Try to learn as much as you can on precision reloading from reputable sources or successful shooter in Long Range or BR shooting. Some very basic methods can reap amazing results.
Food for thought but if you think it is important then it IS IMPORTANT!
Cheerio Ned
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Tim L
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I hear you Ned,
And whilst this probably isn't the right place for it, I will say I am enjoying the journey. Townsville was my first comp (well it followed directly on from the Marian and Mackay Opens so it was my first week of competition shooting) and there was no curve to it; it was a learning vertical !
I took a great deal away with me, including knowledge that there is a great support group for F class shooters that is made up entirely of F class shooters. In fact virtually all F class shooters are part of it, and that is fantastic.
Looking forward to meeting some new faces down in Brisbane,,,,, where my ammo may well have a new angle to the chamfer, but will definitely be shot in order of case weight
And whilst this probably isn't the right place for it, I will say I am enjoying the journey. Townsville was my first comp (well it followed directly on from the Marian and Mackay Opens so it was my first week of competition shooting) and there was no curve to it; it was a learning vertical !
I took a great deal away with me, including knowledge that there is a great support group for F class shooters that is made up entirely of F class shooters. In fact virtually all F class shooters are part of it, and that is fantastic.
Looking forward to meeting some new faces down in Brisbane,,,,, where my ammo may well have a new angle to the chamfer, but will definitely be shot in order of case weight
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KHGS
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G'day Tim,
never be afraid to try something new, but be prepared to ditch something that shows little or no benefit! Always push for new insights to this fascinating game!
Good luck and enjoy the journey!
Cheerio Ned[/quote
Excellent advice! I have been throwing things out for years & I still do things that I know mean little......But they make me feel good!
Keith H.
never be afraid to try something new, but be prepared to ditch something that shows little or no benefit! Always push for new insights to this fascinating game!
Good luck and enjoy the journey!
Cheerio Ned[/quote
Excellent advice! I have been throwing things out for years & I still do things that I know mean little......But they make me feel good!
Keith H.
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AlanF
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Back to the original question about batching cases, I've done some calculations on the effect of variations in case weights. It makes a lot of assumptions, including that 100% of brass volume variation affects case capacity, and it uses a statement I found on http://kwk.us/cases.htm which says "a 4% change in case capacity gives about a 1% change in velocity".
With a 284 Winchester case and typical target loads, a 3 grain variation in case weight will cause about 4.5 fps muzzle velocity variation resulting in about 0.1 MOA of vertical at 1000 yards. This is about the same amount of vertical that would be caused by a 0.1 grain variation in powder charge.
I try to weigh powder charges to BETTER than 0.1 gn, and with that sort of precision in mind, try to keep case weight variation to a grain or two. The thing about vertical is that it usually manifests itself as flyers. And vertical flyers happen when a multitude of things all cause vertical in one direction (up or down). So the more you can do to minimise the MANY types of vertical, the less fliers will ruin your shoot.
With a 284 Winchester case and typical target loads, a 3 grain variation in case weight will cause about 4.5 fps muzzle velocity variation resulting in about 0.1 MOA of vertical at 1000 yards. This is about the same amount of vertical that would be caused by a 0.1 grain variation in powder charge.
I try to weigh powder charges to BETTER than 0.1 gn, and with that sort of precision in mind, try to keep case weight variation to a grain or two. The thing about vertical is that it usually manifests itself as flyers. And vertical flyers happen when a multitude of things all cause vertical in one direction (up or down). So the more you can do to minimise the MANY types of vertical, the less fliers will ruin your shoot.
Watch this space -
Peter, Marty and I did some good scientific testing on this a couple of years ago and I have promised to write this up properly. It will dispel some rumours and myths.
Some hints at what is to come when I finally get the proverbial finger out.
We tested Winchester 284, Lapua 284 and Remington RSAUM brass weights vs volumes with H20 and other methods (quite scientifically and very accurately) and plotted speeds against volumes and methods with various other calculations. The aim of this exercise was to try and determine the validity of some methods and whether they were worth doing (in particular weight sorting - worth it or not???)
Another Tease - Using Quickload (cheating a bit instead of doing my own internal ballistics calculations) Varying the case volume of a 284 brass with same load data from 65 grains H20 to 66 Grains H20 gave a calculated velocity decrease of 19 fps. For a 284 at 1000 yards this is roughly equivalent to 1/2 a minute of elevation and could drop you out of the 6 ring........ - Can you see this much variation in brass - You betcha!
What is the equivalent drop for a 200 yard Benchrest 6PPC doing 3400 fps and a 19-20 fps drop = immeasurable (try it for yourself and enter the data into a ballistics program) - There is no comparison - please don't make any........
For those that are now weighing to the kernel of powder - this is the equivalent of 1-3 fps why would you not want to control the volume of cases to same degree???? (need 0.5-1 grain weight variation of cases for same order of magnitude variation)
Peter, Marty and I did some good scientific testing on this a couple of years ago and I have promised to write this up properly. It will dispel some rumours and myths.
Some hints at what is to come when I finally get the proverbial finger out.
We tested Winchester 284, Lapua 284 and Remington RSAUM brass weights vs volumes with H20 and other methods (quite scientifically and very accurately) and plotted speeds against volumes and methods with various other calculations. The aim of this exercise was to try and determine the validity of some methods and whether they were worth doing (in particular weight sorting - worth it or not???)
Another Tease - Using Quickload (cheating a bit instead of doing my own internal ballistics calculations) Varying the case volume of a 284 brass with same load data from 65 grains H20 to 66 Grains H20 gave a calculated velocity decrease of 19 fps. For a 284 at 1000 yards this is roughly equivalent to 1/2 a minute of elevation and could drop you out of the 6 ring........ - Can you see this much variation in brass - You betcha!
What is the equivalent drop for a 200 yard Benchrest 6PPC doing 3400 fps and a 19-20 fps drop = immeasurable (try it for yourself and enter the data into a ballistics program) - There is no comparison - please don't make any........
For those that are now weighing to the kernel of powder - this is the equivalent of 1-3 fps why would you not want to control the volume of cases to same degree???? (need 0.5-1 grain weight variation of cases for same order of magnitude variation)
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johnk
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Dave,
A couple of questions:
Reason I'm asking is that that 30-284 I'm playing with has significant case weight differences after I prep the brass to enter the chamber, several grains. I'm not surprised because with the turned neck chamber, I had to do some rough run-it-up-to-the-stop turning to ensure that all the cases would crush chamber first time. The process turned out nicely fitted brass though, but once I've finally fireformed the lot & uniformed the primer pockets, I'm going to have to run a real case by case weight cf volume test, or more likely, sort them on volume.
Incidentally, is it only the latest lot of Lapua that has the funny primer pockets? Out of the box, mine have a distinctly deeper perimeter, as if the cup were struck with a ring or a punch with a rebate, and the centre is proud. I didn't touch them before fireforming, but nearly crapped myself when I uniformed after first firing & all that brass came out. I thought that I'd overadjusted my Lee universal depriming die or blown the arse out of soft brass until I went back & looked at the raw brass - raw, a somewhat less apt word word than virgin. I recall somebody on BR Central being concerned of the same issue prior to my discovery & he was accused of maladjusting his dies.
John
A couple of questions:
- Does Lapua make 284 brass or are you talking of 6.5 necked up?
Are you talking of raw brass weight or after it is prepped/neck turned/uniformed/fireformed?
Reason I'm asking is that that 30-284 I'm playing with has significant case weight differences after I prep the brass to enter the chamber, several grains. I'm not surprised because with the turned neck chamber, I had to do some rough run-it-up-to-the-stop turning to ensure that all the cases would crush chamber first time. The process turned out nicely fitted brass though, but once I've finally fireformed the lot & uniformed the primer pockets, I'm going to have to run a real case by case weight cf volume test, or more likely, sort them on volume.
Incidentally, is it only the latest lot of Lapua that has the funny primer pockets? Out of the box, mine have a distinctly deeper perimeter, as if the cup were struck with a ring or a punch with a rebate, and the centre is proud. I didn't touch them before fireforming, but nearly crapped myself when I uniformed after first firing & all that brass came out. I thought that I'd overadjusted my Lee universal depriming die or blown the arse out of soft brass until I went back & looked at the raw brass - raw, a somewhat less apt word word than virgin. I recall somebody on BR Central being concerned of the same issue prior to my discovery & he was accused of maladjusting his dies.
John
Hi John,
This is 6.5*284 Brass (sorry for the error above) opened up to 7mm and turned.
The point should very clearly be made that you should weight sort after prepping to whatever you do. If you neck turn and trim and uniform primer pockets - do that before weight sorting - not after. You can do it before but it will be a rougher correlation with end volume than if done before. Also try and do it on cleaned brass (or new unfired). Every firing can lay down quite variable carbon deposits in the case (in order of 10-20 mg per firing (0.15-0.3 grains in the cases we checked)). If you don't neck turn or uniform etc then just do it on the raw brass - it still gives a very good result.
If you turn off some brass in neck then sure the weight will be reduced but this will be pushed to outside in chamber and increase internal volume in the respective ratio. They do not need to be fireformed to weigh but they do to test volume.
My advice -Don't worry about volume sorting - A hell of a lot of work that could ultimately be far less accurate than brass weighing depending on uniformity of head in brass and your volumetric method. For a single batch of high quality Lapua brass - sorting by weight almost certainly should give a very good result. In our testing of a few batches - as accurate at least as the best volumetric analysis we could do and far better than we could achieve with H20, powder, fine ball bearings and other volumetric measurement methods (Metho proved to be the best system we investigated and can be done quite scientifically - albeit painfully and not one I would recommend for day to day use)
Weight sorting brass is a very easy job to do and with electronic scales (as opposed to beam balance which can be tedious) is a one off job that can be done very quickly - I can do 100 cases in under 10 minutes.
It is not for everyone and not worth doing for ranges <800 yards with good brand brass but for the long range boys and girls I would highly recommend it as a very simple step that has a small but significant influence on elevation.
AND REMEMBER: Total vertical dispersion deviation is the square root of the sum of the squares of all these small errors. They are not simply additive. It is very hard to measure their individual effect on a target because of the overlapping other errors but if approached scientifically you can determine its effect. You will not easily determine it by shooting a few 5 or 10 shot groups but the improvement will be there. - It is far better to look at a correlation graph from one extreme to the other and look for a relationship between elevation/speed and volume/brass weight - not group size/score with sorted vs unsorted - you have no power in your test method due to large variation (or sd) and small sample sizes.
Oh and as a rough guide to the variation we have seen in batches of cases - Winchester - 4-7 grains, Lapua 2-4 grains (some Lap Palma 308 cases had under 2 grains variation and arguably not worth sorting), Remington 4-6 grains
This is 6.5*284 Brass (sorry for the error above) opened up to 7mm and turned.
The point should very clearly be made that you should weight sort after prepping to whatever you do. If you neck turn and trim and uniform primer pockets - do that before weight sorting - not after. You can do it before but it will be a rougher correlation with end volume than if done before. Also try and do it on cleaned brass (or new unfired). Every firing can lay down quite variable carbon deposits in the case (in order of 10-20 mg per firing (0.15-0.3 grains in the cases we checked)). If you don't neck turn or uniform etc then just do it on the raw brass - it still gives a very good result.
If you turn off some brass in neck then sure the weight will be reduced but this will be pushed to outside in chamber and increase internal volume in the respective ratio. They do not need to be fireformed to weigh but they do to test volume.
My advice -Don't worry about volume sorting - A hell of a lot of work that could ultimately be far less accurate than brass weighing depending on uniformity of head in brass and your volumetric method. For a single batch of high quality Lapua brass - sorting by weight almost certainly should give a very good result. In our testing of a few batches - as accurate at least as the best volumetric analysis we could do and far better than we could achieve with H20, powder, fine ball bearings and other volumetric measurement methods (Metho proved to be the best system we investigated and can be done quite scientifically - albeit painfully and not one I would recommend for day to day use)
Weight sorting brass is a very easy job to do and with electronic scales (as opposed to beam balance which can be tedious) is a one off job that can be done very quickly - I can do 100 cases in under 10 minutes.
It is not for everyone and not worth doing for ranges <800 yards with good brand brass but for the long range boys and girls I would highly recommend it as a very simple step that has a small but significant influence on elevation.
AND REMEMBER: Total vertical dispersion deviation is the square root of the sum of the squares of all these small errors. They are not simply additive. It is very hard to measure their individual effect on a target because of the overlapping other errors but if approached scientifically you can determine its effect. You will not easily determine it by shooting a few 5 or 10 shot groups but the improvement will be there. - It is far better to look at a correlation graph from one extreme to the other and look for a relationship between elevation/speed and volume/brass weight - not group size/score with sorted vs unsorted - you have no power in your test method due to large variation (or sd) and small sample sizes.
Oh and as a rough guide to the variation we have seen in batches of cases - Winchester - 4-7 grains, Lapua 2-4 grains (some Lap Palma 308 cases had under 2 grains variation and arguably not worth sorting), Remington 4-6 grains
Last edited by DaveMc on Sat Jul 12, 2014 3:29 pm, edited 2 times in total.
Thanks to all who responded to my original question.
Results from my initial batch weighing. I picked one case at random and zeroed my electronic scales. Out of 200 new Lapua .308 cases 82 were on the zero weight. I must of been lucky! 3 were -.6gr, 1 -.8, 1 -1. The rest populated the heavier range with an average of 12 or so weighing + .5- + 1.1 in .1 gr increments. Total spread was -1.1 to + 2.1.
I then opened another new box and weighed another 100 and found 42 were at my "Zero" weight.
Some food for thought...
Phill
Results from my initial batch weighing. I picked one case at random and zeroed my electronic scales. Out of 200 new Lapua .308 cases 82 were on the zero weight. I must of been lucky! 3 were -.6gr, 1 -.8, 1 -1. The rest populated the heavier range with an average of 12 or so weighing + .5- + 1.1 in .1 gr increments. Total spread was -1.1 to + 2.1.
I then opened another new box and weighed another 100 and found 42 were at my "Zero" weight.
Some food for thought...
Phill
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