I have 200 new Lapua cases that I'd like start loading up this weekend. I know lots of guys weigh them first and toss out abnormalities. My question is: what is an acceptable margin to work with? For example, I weighed 20 cases and they weigh 167 gr +/- 0.5 gr. How far off should they before I get concerned?
Weighing / Sorting New Lapua Brass
- Thread starter quebow03
- Start date
Don’t weigh the brass, it screws with your head and doesn’t yield the desired results
In the everyday sniper podcast episode 125 mike and Adam of MHSA discuss load development and Adam (learned reloading in BR) discusses why it is not a good way to determine brass consistency. Is the extra weight in the rim? Case head? Shoulder? Neck? We don’t know, extra weight in the rim or head is irrelevant
Extra weight in the neck might be relevant, but is the brass concentric? If it is concentric and equal in volume (or nearly so) it is gonna shoot fine
In the same brand/lot of brass small weight fluctuations do not mean there will be small volume fluctuations
In the everyday sniper podcast episode 125 mike and Adam of MHSA discuss load development and Adam (learned reloading in BR) discusses why it is not a good way to determine brass consistency. Is the extra weight in the rim? Case head? Shoulder? Neck? We don’t know, extra weight in the rim or head is irrelevant
Extra weight in the neck might be relevant, but is the brass concentric? If it is concentric and equal in volume (or nearly so) it is gonna shoot fine
In the same brand/lot of brass small weight fluctuations do not mean there will be small volume fluctuations
I recently bought a box of Lapua 308 brass that had a weight range of 173.2 to 176.5. This was a much larger range than I've seen with Lapua brass. I wrote to customer service and they said that they regulate the interior volume of the case and where weight variation occurs is when they cut the extractor groove. So it sounds like we should just shoot Lapua brass.
I wouldnt bother myself. If you are going to do it I would do so after they are shot, sized and trimmed so that you can attempt to make them as uniform as possible so that the weight isnt due to a slightly longer neck etc.
Water weighing is the better way to sort, its just messier. But it allows a more direct measure of volume as compared to just material weight. You use a plug in the primer pocket for all cases to stop leaking and then fill them up tot the same level with water or alcohol and weight them.
Water weighing is the better way to sort, its just messier. But it allows a more direct measure of volume as compared to just material weight. You use a plug in the primer pocket for all cases to stop leaking and then fill them up tot the same level with water or alcohol and weight them.
Like spife said, weighing the brass not the best method. Find the 173.2 case and the 176.5 and do the water capacity thing, it may answer your questions. If you are shooting 1K benchrest, you'll want to bring your 50 best cases to the match, for the rest of us, not so much.
I started weighing brass and quickly realized if I start this, what's the next thing I do down this rabbit hole? Once you start weighing cases, you'll move on to another variable that doesn't matter. Pretty soon, you're too far in and it messes with your head.
Just load em up making sure the neck tension is consistent.
Just load em up making sure the neck tension is consistent.
There was a cool catch phrase on here a few yrs ago, "you can't shoot the difference", aimed at newer shooters entering the PRS game. If you ignore too many of these, never be in the game either.
What happens when your “heavy” case is the straightest, most concentric “perfect” case but is a little heavy? Case weight isn’t sa good indicator, so don’t waste time weighing cases
Other factors can matter more
Concentricity? Yes
Case volume (water weight)? Yes
Neck thickness? Yes
Other factors can matter more
Concentricity? Yes
Case volume (water weight)? Yes
Neck thickness? Yes
Quite a bit of weight variation can come from the head and extractor groove without affecting case volume.
Here is what 8 grains of brass shavings looks like. Doesn't seem to me that it would take much solid brass to vary up or down 4 grains. The primers in the picture are large rifle. The cartridge is a 6.5 Creed.
Consider the extractor cut within the same lot of brass was made with the same cutter in one pass. Watch a video of brass being made.
In any event, plus or minus one grain on a 308 case does not mean anything in terms of ES/SD.
In any event, plus or minus one grain on a 308 case does not mean anything in terms of ES/SD.
It can cause up to almost a grain of variance depending on the size of the part, which yes, on a 308 does not mean a ton, but that can account for fair portion of the total weight variance from part to part where the weights vary but headspace lengths and internal volumes can remain much more consistent.
According to Brian Litz weighing brass is an outdated method to reduce variables. New Manufacturing methods and quality components make this not necessary. Also he says that he wasnt able to prove in his lab that it effected MV or SD.
I've not seen a case be made -pun- for weight differences equaling internal dimension differences.
I used to do it but after listening to Brian I dont waste my time. I even did several tests with sorted bullets and sorted brass. Ironically when I used my "out of spec' bullets and out of spec brass together I shot the two best groups of the testing.
Now I buy quality components and use them all no sorting.
I've not seen a case be made -pun- for weight differences equaling internal dimension differences.
I used to do it but after listening to Brian I dont waste my time. I even did several tests with sorted bullets and sorted brass. Ironically when I used my "out of spec' bullets and out of spec brass together I shot the two best groups of the testing.
Now I buy quality components and use them all no sorting.
D
Deleted member 113831
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Surely there was a difference, or else why spend the money for "quality" brass? If consistent weight isn't one of the things that determines brass "quality", then what would you say does?
It's all about the goals of your reloading. When you buy brass you're not buying it for consistant weight. If your reloading goal is to shoot ammo where all the components weight the same then weight sort. If your goal is to shoot steel at 1k yards than weight sorting should equal one or both of the following smaller groups or SD. Testing that is fairly easy.
Do your own testing. If it works do it. I'm just telling you what Litz said mirrors my testing.
It's all about what are your goals, and is what your doing getting you closer to those goals.
Some of the older techniques are no longer needed with quality components.
If you are using range pick up LC brass than you will see a difference by weight sorting and extensive brass prep. If you're using Lapua you most likely wont.
Do your own testing. If it works do it. I'm just telling you what Litz said mirrors my testing.
It's all about what are your goals, and is what your doing getting you closer to those goals.
Some of the older techniques are no longer needed with quality components.
If you are using range pick up LC brass than you will see a difference by weight sorting and extensive brass prep. If you're using Lapua you most likely wont.
I don't weight sort new Lapua brass but I do sort them by the base to datum line on the shoulder and bump all that are over the average back since I skim cut the necks for a 85-90% clean up.
Still not necessary but have all the tools to do it and I'm not losing brass at matches just casual shooting and hunting.
Still not necessary but have all the tools to do it and I'm not losing brass at matches just casual shooting and hunting.
D
Deleted member 113831
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Thanks for fleshing that out a bit. I wasn't trying to be a dick. You were making somewhat contradictory points. You were saying that with modern quality components you shouldn't see any benefit from weight sorting.....but, then admitted that shooting LC might require sorting.
I tend to agree with BOTH points. That begs the question then, how much difference is too much?
So this is Lapua brass with a 1.9% total range in weight.
This sounds like the perfect case (pun) to measure volume differences between the lighest and heaviest from a single lot of Lapua brass.
I'm going to make a guess that the water weight will differ by about one forth of the brass difference or about 0.8 grains of water.
Will that make a difference down range? Take both of those cases on an expensive hunting or target trip and find out.
Maybe the weight difference is in the rim/grove, or maybe it's body thickness, or neck thickness, maybe a thin or thick section when the case was formed.
When you sample enough parts, there will be distribution and a high and low outlier. Find the mean, determine the standard deviation of the lot (a lot size of 100, 200, etc) step out in both directions about 3 SD. The few that are outside that are NOT like the rest. Shoot them if you want, but they are NOT like the rest.
Something is different about them.
Here's some 22 Nosler brass sorted. Same lot. Actually complete cartridges. Projectiles? Powder charge? Primers? or
Case weight?
Litz says that weight isn't going to matter. I say the machine or operator screwed up on three of these.
Anyone want to shoot mistakes?
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If you are going to weigh anything, it should be water volume AFTER you have fired the case (expanded). The most accurate way to do this is cap the neck with a bullet seated at a know depth, inject water through the flash hole, and plug the primer pocket (I use 21st Century plugs). If you weigh the case with bullet + plug, then subtract it from the weight of the now water filled cartridge, you have the volume for that case. It takes a very long time to do this so I only do it on brass that is used for compressed loads shot from the bench.
As for case weight, as everyone else has stated, it means nothing. As for volume, Lapua is consistent, Peterson is consistent, Nosler is not, Norma is not, Hornady is not. Still, if you feel the need to have tight consistency on volume, you will cull out at least 10% of Lapua and Peterson.
As for case weight, as everyone else has stated, it means nothing. As for volume, Lapua is consistent, Peterson is consistent, Nosler is not, Norma is not, Hornady is not. Still, if you feel the need to have tight consistency on volume, you will cull out at least 10% of Lapua and Peterson.
It's not contradictory in the slightest. Very simple, weight sorting, neck turning, internal volume water testing, all that is not needed with modern quality brass like lapua. It is going to make a small difference with crap brass like LC. It's not admitting anything. LC and Lapua are apples to oranges. My statement of quality brass doesnt include lc.
It's easy to test. If you test several samples of each you should have your answer. It's totally fine to disagree the results dont lie. I'm not mad or trying to convince you. I'm letting you know Litz perspective and my testing results. I'm encouraging you to test it out for yourself. Only you can prove it to yourself.
There is a case to be made for extensive case prep on crap brass from a cost perspective. However in typical prs matches the improvement in brass prep on bad brass isnt as important as mastering wind and distance calls.
IMO not worth it on Lapua brass. I got better results expanding the necks on new brass rather than wasting my time weighing. Two totally different things but I chose to use my time there.
D
Deleted member 113831
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The only brass I've weight sorted is LC 308, and I don't honestly recall the amount of reduction in group size. I did the test years ago. It was enough however, that I decided to continue the practice. My all around reloading skills have improved somewhat in the last 10 years or so, maybe it's time for another test.
