Brass Sorting

G

gorillamotors

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I know a lot of people sort their brass but does it REALLY make a big difference in F Class competition? Does it change the POI? The ES? The velocity? I have tested cases from the same manufacturer with a case weight spread of up to 4 grains and I have experienced no change in the velocity, ES or POI of the 140 g Berger hybrids at up to 300 yards.

I know that turning necks to uniformity DO indeed help.

Jim
 
I have a significant amount of carefully gathered test data which shows that sorting brass by weight helps make slightly smaller groups. However, that data is NOT the same thing as proof. Proof requires a LOT more testing because teasing meaningful small changes in group size out of a procedure which tends to produce group sizes much larger than the expected improvement ain't easy.

In other words, any improvement (if it exists at all) has a tendency to be hidden in the data noise. My test results may very well be invalid. But at least they're carefully measured by scanning 5-shot groups, using target scoring software, and studying the data in with the help of Excel and the associated graphs.

I select 70 identically prepared cases for my F/TR matches. Then I weigh them into light, medium, and heavy piles. Let's say the heavy pile has 20 and the medium 26. In that case I find two of the heaviest "medium" cases and shift them into the heavy pile. The goal is to have 20 scoring rounds plus at least two sighters in two of the piles and the third pile with 20 scoring rounds plus 5 sighters.

Then I load three 20 round strings, plus sighters, keeping similar cases together.

This procedure doesn't discard any brass and it only takes a few minutes to do. Does it actually work? Well I think it does, or at least I think it might work Of course it might be about as worthwhile as being sure to wear my lucky underwear.

One thing I know. I started this three months ago and I've won or placed second in every F/TR match since then. Of course, your results may very.

Just be sure to use your lucky underwear EVERY time. All the winners do, although many will deny it. :D
 
Sorting usually means separating by headstamp and lot and load history. If you are talking just about weight, that only works if the cases have identical exterior dimensions or displace the same amount of water with air trapped inside. If that isn't so, then your weight difference may be due to a thicker wall or rim on one case and not affect internal capacity at all. Most manufacturers mix brass that comes off multiple tooling sets into one lot, so a single lot or headstamp and year doesn't necessarily guarantee identically proportioned cases, so you can't be sure of having that without measuring. The usual way is to is to measure what is called case water overflow capacity, which is a measure of how much water the case hold with it filled level with the case mouth (no meniscus). This is done by weighing dry and filled and is given as the weight difference in grains of water capacity. The cases are fired cases with the spent primers still in place (a convenient water plug) because the fired case hasn't yet been elongated by resizing and because cases operating at high power rifle pressures expand before the pressure peak is reached, and thus their expanded size reflects the volume the gases see in the chamber area, not the resized capacity.

If you could assume the exteriors of the cases had identical volume, then Wm. C. Davis found decades ago that for most rifle cartridges, regardless of size, two cases have to be different by 16 grains for there to be a 1 grain difference in the charge weight needed reach the same velocity. So your 4 grain difference is about equal to a quarter of a grain of charge variation or plus and minus 0.125 grains. Normally, the effect of a difference that small is lost in the noise of other factors contributing to your velocity SD. In other words, you would do better to spend your time on things like perfecting your priming technique, getting the same bullet hold in each round, and getting concentric runout to zero. Then you could go back and play with case weight.


Mozella,

If you keep track of group size before and after, Excel has tools (T-test) that will tell you the confidence you can have that your effort is actually making a difference.

Better still, if you use the On-Target program (free early version here) to look at scanned target images, you can learn the center of each group fairly precisely and from that learn the standard error (the standard deviation of the radial standard deviation; how much your group centers wander around from one target to the next) and the distance from the individual holes to each hole center to apply the T-test to for better resolution than group size alone gives you. Group size is influenced too much by random extremes, while using radial SD mitigates that influence.
 
Where I shoot F class it is shot at 600 yards
and it makes a big difference at that range

Anything that shrinks a group in competition is worth the effort
 
While not your typical "F Class" cartridge, I have a very recent example to provide as a reason for sorting when precision matters.

.30 WCF
150 gr Speer HCRN (discontinued :()
2.545" COAL
2.228" case length
32.5 gr IMR4895
WLR primer, lot *638G
Tested in "tight"-chambered 16.25" barrel. (Loose by match standards, very tight by production .30-30 standards.)

Load initially developed in FC brass (single lot).

Load later tested in other brands of brass.

Benchmark velocity (FC brass): 2118 fps
R-P brass: 2066 fps
Win brass: 2161 fps
W-W brass: 2144 fps
R-P brass, lot 2: 2226 fps


All extreme spreads were under 50 fps - most under 30 fps.
Standard deviation peaked at 19.98 fps for the R-P brass (lot 2). All others were 13 fps or less.

If you didn't catch it, the two different lots of R-P brass were 160 fps apart (7.7%).
I have not weighed, nor checked H2O capacity of either lot; but I can tell you that lot #2 was from the '60s or '70s and the other lot was from about 2010. Externally, though, they look exactly the same.
Same components.
Same conditions.
Loaded at the same time.
Fired at the same time.
Dramatically different result.


Mix one of those 2226 fps bad boys in with the already-slower 2066 fps lot, and you'll have a flyer. In this case, it isn't just the trajectory that matters, either. When this load hits 2,200+ fps, the groups scatter - ragardless of brand of brass.

For these particular loads in R-P brass, fired from that rifle, the velocity difference results in a 2.25" higher point of impact at 200 yards. And the difference is 6.1" at 300 yards. Significant.
 
Again, same brand, same lot, and that saves you most of the potential grief if you don't find a wide range from tooling differences. Fine tuning wise, same load history so work hardening of the necks matches and gives more closely matching bullet pull.

Old brass, as FrankenMauser found, is another factor. Most military 30-06 from Lake City weighs around 194-196 grains average. Most commercial is that or slightly lighter. I've had one lot of Winchester that weighed 180 grains. At the other extreme, though, Wm. C. Davis, Jr. had the example of a Peter's 30-06 case from the 1960's that weighed 214 grains, IIRC. So that's a 34 grain span, or a little over 2 grains worth of powder difference.
 
Sorting

Hello I bought some Hornady brass for a 300 win mag and did everything to them take them clones of each other I sorted them into 10th s of a grain as well as the Hornady AMAX and the powder !! After carful selection I ran a string of 10 rounds with a variance of a mere 17 fps I say yes sorting is effective at extreme long range but not 100 yards !! 17fps will be almost 10 bulls eyes at 1400 yards!!
 
I know a lot of people sort their brass but does it REALLY make a big difference….?
Click to expand...

I do not have ‘the Sergeant syndrome’, long before the Internet a shooter/reloader writer for rag magazines purchased 500 cases from one lot. He sorted, separated and culled the casers. He matched the culls in lots; when finished he settled on 47 cases out of the 500 that were worthy of being called match.

He then started test firing; he found he could index a case with a powder column that was not centered in the case meaning the case was thicker on one side than the other, when indexed the case was as accurate as the perfect matched cases. When he did not index the case when fired the results would appear on paper like a flyer.

I am the only one that read the article; that is the reason I do not start out like I discovered sorting cases. Then there is that part about what makes a difference; I measure case head thickness, I have found cases that have a case head thickness of .200”, I have found cases with case head thickness of .260”. Sorting cases by weight is cute but the length of the powder column only makes a difference if we are talking about the difference between the 30/06 and 308W; meaning the powder column in the 308 W is shorter and larger in diameter then the powder column in the 30/06.

F. Guffey
 
Hy.
I am too new and unexperienced on bigger calibers than .223
But I compete in benchrest and precition shooting.
If you want a group of 1 inch at 300 yds. There are too many variables on the equation of reloading. Each variable is as important as the others. Just forget one variable and forget your nice group. (I am talking about .223)
To sort the brass is very important. Brand and times shooted is important. For a championship I also weigh the brass.
Result of taking care of every reloading detail gave me the second place in my state for the last two years. There is some detail I am still missing to get the first place.
 
It seems that consistency and repeatability is one of the keys for accuracy. In all honesty I suspect that part of the reason some folks notice/say it does make a difference is because the type of person who sorts, trims every time, and even weighs cases, also are the same super detail oriented types who are very very particular about every single part of their loads and shooting and thus make very consistent and repeatable loadings. Me I am not a sorter, but also not a target competitor either, and will never be the equal of any of the long range shooters.
 
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