thx for the reply. i am assuming this is the "good stuff", like norma and lapua?
murf
!! disregard the question, walkalong. i just read the previous post. thx again.
For those that separate and weigh their brass.. whats your tolerance?
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murf
!! disregard the question, walkalong. i just read the previous post. thx again.
Just a thought, it may sound silly but it's not. Think about it.
During combustion, the brass quickly expands to fill the chamber.
The burning powder experiences that larger volume.
THAT volume should be of concern to you.
Not the volume of new brass, nor the volume of resized & trimmed brass.
New brass and resized brass will expand to match the chamber,
expanding the internal volume inside the case during discharge.
When the brass is fully expanded, the actual combustion volume
is reduced only by the amount of brass taking up space inside the chamber.
Whether you weigh the brass or measure its internal volume,
the actual task is to normalize combustion volume during discharge.
During combustion, the brass quickly expands to fill the chamber.
The burning powder experiences that larger volume.
THAT volume should be of concern to you.
Not the volume of new brass, nor the volume of resized & trimmed brass.
New brass and resized brass will expand to match the chamber,
expanding the internal volume inside the case during discharge.
When the brass is fully expanded, the actual combustion volume
is reduced only by the amount of brass taking up space inside the chamber.
Whether you weigh the brass or measure its internal volume,
the actual task is to normalize combustion volume during discharge.
Demi-human
maybe likes firearms a little bit…
These are exactly my thoughts. Many say that the case should be trapped in a sizing die to avoid any variance from spring back.
I wonder if the rear of the case, the part that "shouldn't" expand, may also contribute to differing velocities. As, maybe, individual cases, which weigh the same, expand to differing rates at the rear of the chamber. Changing the specific volume of the chamber.
I wonder if maybe one might drop a case into a measured cylinder and see how much water is displaced by the case. This could tell how much volume is taken up in the chamber.
And, as was said earlier, yes. Water weighing for internal volume is the most precise. It is also quite laborious. After doing some weighing with and without water, sorting bullets and grouping heavy cases, light cases and exact weight bullets, and a group of mismatched cases, I found that I can not shoot the difference.
Some can, obviously. I can not. If one can shoot this tight, than case segregation will shave tenths off of an average. Volume weighing being most exacting, and case weight being expeditious. And none of this will work if the rifle is not up to the task, as we are now venturing onto the border of custom territory.
Interestingly, the mismatched cases shot the best. I then understood the phrase "shoot the difference". I now save the advanced techniques for when I am able to. This gives me more time to practice, enabling me to reach the advanced techniques sooner.
I still separate bullets and cases, just while they are dry. And to the original question, I group them by three tenths. I still weigh powder on a Gempro and measure each bullet to the ogive. These things bring me confidence. Perhaps volume measurement will do the same for others.
scythefwd
Member
ant.. true, but I have no way of exerting 60k psi to mimic that environment while still being able to measure it.
edwardware
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I EXPERIMENT!
Goodness it's not that hard. Weight 50 cases, group the heaviest 10 and lightest 10, and go shoot across your chrony.
The same goes for weighing charges vs throwing them; throw 50 charges to a scale, note the min and max charge weights, load 10 rounds each weighed at min and max, and go shoot.
Then you will KNOW something instead of just speculating. Better yet, you will save yourself lots of time because you won't spend hours tediously sorting and weighing for an improvement too small to detect.
Blue68f100
Member
I ran an experiment a while back that I just loaded up the rounds and shot them all over the crony, noting any POI. Afterwards the ones that were off on the SD (velocity), I ran std dry weight and ran volume capacity test. I also rand 10 that did the best for a reference. The conclusion I found was that none of it made much sense. Weight by volume did not correlate with volume weight about 1/2 the time. The problem is that just standard deviation in weight/volume does not always match internal volume and other variables. I used a GP250 for all weighting. If your going to do water volume test you should add a drop of surfactant (soap) to the water. Helps the wetting along the walls. If you really want to get a good volume test you need to load a bullet to you OAL and fill from the primer hole. This way you eliminate the variables related to the neck of the case.
A better way is to shoot the loads and cull any that give you a larger deviation. Save those for fouling. The biggest unknown is the environment in which you shoot. Wind is a constant variable that's constantly changing. So it makes it hard to know for sure if it was the bullet, operator or environment that made that one bullet do something different.
A better way is to shoot the loads and cull any that give you a larger deviation. Save those for fouling. The biggest unknown is the environment in which you shoot. Wind is a constant variable that's constantly changing. So it makes it hard to know for sure if it was the bullet, operator or environment that made that one bullet do something different.
ArchAngelCD
Member.
I agree and I will add, some of the most accurate ammo I have seen tested had high SD numbers sometimes in triple digits.
Poper
Member
I go one more step and sort bullets by diameter, too.
I have found bullets often vary widely from lot to lot and oftentimes from box to box with most manufacturers, particularly Hornady, Sierra, Barnes, Nosler and Speer. The most consistent bullet makers I have used are Berger and Lapua. I use Lapua 108gr. Scenar in my 6.5x55SE for high metallic silhouette, which is sometimes iffy for the rams, and 140 grain Berger in my .270 Win. (Tikka) also for high power metallic silhouette. Both Lapua and Bergers have been so consistent over the years that I no longer weigh and measure them, except for seating to .001" from base of the cartridge to the bullet ogive using a RCBS precision mic and a Redding micrometer seating die.
Of course I have never been accused of being OCD or anything......
So it does make a difference? The bullet has no idea who or why it is being shot...benchrest, plink or whatever. Anyhoo, I havent used mine, but the OP is questioning folks who sort and to what degree. My shooting doesnt seem to warrant it, and so far I only have 2 separations: mixed headstamp, ( growing smaller) and LC. I am going to get some Lapua, and some of Starlines new rifle brass, which will both remain separate.
Russellc
FROGO207
Member
I tried sorting by headstamp first and then by weight as well when the accuracy bug bit me hard. I found weighed to .3 grain tolerance I could not shoot the difference with a quality 270 or a 30-06. I do hand weigh the charges to .1 grain and the bullets to .5 grain for my good loads but that is as far as I go these days. YMMV
243winxb
Member
To sort by .3 gr , the brass needs to be all the same lot, new and unfired. Then sized , trimmed to the same length, flash hole done. Turn neck, if needed. Then sort by 3/10 th gr.
But first have a rifle that may benefit from your labor.
But first have a rifle that may benefit from your labor.
ReloaderFred
Member
I'm still of the belief that weighing doesn't tell you where the extra weight is in a slightly heavier case. With the discussion of weighing in groups of .3 grains, does that mean that if a particular case weighs .3 grains more than another that if I take a file and remove .3 grains from the rim of the heavier case that it will shoot the same as the lighter case? Without actually measuring the volume of each case, it's all speculation as to where the weight variances are.
Hope this helps.
Fred
Hope this helps.
Fred
So true. My original point was that due to the density of brass, measuring weights to small tolerances doesn't do much to ensure constant case capacity.
I suspect not many matches were won because someone's brass all weighed the same either.
lol, no, it's because they are the best shooters. But, it's a proven fact that well prepped consistent brass shoots better. For those that can shoot the difference anyway. It's not huge, but it is there, and when folks are winning and losing aggregates by such small margins, it matters. 
witchhunter
Member
I would see way more improvement if wasn't drinking a Pepsi and smoking a Montecristo while shooting than weighing my brass. If you are serious about it, measure the volume and sort accordingly. Do all the prep, including primer pockets and flashholes, trimming and turning before you measure. I am a squirrel shooter and I do all the prep, (I hope it helps). I used to have a friend that was a benchrest guy and he would sell me all of his brass that was out of spec. I loved it! Fully prepped and ready to load .222 brass for cheap. He thought he could shoot the difference, I knew I couldn't. I am currently working up a load for a new rifle, one load shot 3 groups today that averaged .246. I came home happy, it was a good start. That would have been good for like 190th place at Camp Perry. See where I am going with this? I shoot a single group in the high .100s and I am tickled. Benchrest guys shoot those all day everyday.
Nature Boy
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hey, when you're done weighing and sorting your brass, don't forget your bullets. Weigh those too, then measure their base to ogive, then trim the meplats, then point them....
Or, you could take up gardening before it's too late
Or, you could take up gardening before it's too late
Demi-human
maybe likes firearms a little bit…
Or, you could take up gardening before it's too late
I consider my garden the work and weighing bullets and brass fun.
Did you fl size and trim before weighing that may tighten up the variance a little, either way that is still very good. It will be more important as you reload the brass more, if you have not already worked up a load, load developing can really cause variations in the brass
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