308 range brass analysis

[AJC1]

Trying to collect data to better understand brass quality and selection based on consistency. It could apply equally to hunting or target shooting in handoading for accuracy. Consistency is the key to accuracy so I'll start at the beginning the beginning with the case. All brass is range pickups and believed to be once fired. The ppu was fired in my gun so I have first hand experience. The s and b was collected at an indoor range and the federal was shot by a friend. The rest is unknown but anilized for a larger data set. I kept measuring to batches greater than 10.

 

[AJC1]

The rest of the data. Many of the groups of cases could have the es of the group vastly improved by removing an outlier. Sometimes removing two helped a lot and some groups were spread over a wide range. Federal and Remington had large groups next to each other making for great lots of 50 cases. Some like ppu were all over the spectrum with no big groups.

 

[CoalCrackerAl]

Im a little confused. Are the numbers case length? I trim mine to all the same length.

 

[AJC1]

Im a little confused. Are the numbers case length? I trim mine to all the same length.

The numbers are case weight to the tenth of a grain. There is a correlation to capacity but I haven got that far yet.

 

[CoalCrackerAl]

Ahh ok i see. Interesting how they vary. I only weigh a case when im setting up a powder charge.

 

[TEXASJD]

Ya the next step after weighing them is water volume.

 

[AJC1]

its easy to see the best cases for groups. Ppu vs RP

 

[AJC1]

Ya the next step after weighing them is water volume.

I was wondering what the best time was for that. After full prep or after fired in my chamber. As long as the cases are tested in the same way the test will compare them to each other. My inital plan is to eliminate all outliers and show that even if sorted by headstamp further checks may still be important even for casual shooting. Winchester was way worse than I anticipated.

 

[TEXASJD]

https://www.sinclairintl.com/reload...s/sinclair-concentricity-gauge-prod37479.aspx

one of these will help answer some questions too

 

[TEXASJD]

I normally start with new brass through this process (Lapua)

 

[Reloadron]

I played this game or as my wife calls them my little science experiments. So here is what I did. I randomly selected 10 cases each of Remington, Winchester, WCC 10, LC 13 and Federal. All of the brass was sized and trimmed to nominal. Every effort was made to get the best uniformity possible.



Modeling clay as used in glass bedding was used to plug primer pockets which is represented by the 1.8 grain tare weights. I hope to get this brass loaded and shot over the chronograph this spring summer. Something to note when doing stuff like this is manufacturers do not all use the same brass composition. I forget which is which but some are 80/20 and some are 70/30. The 80/20 copper zinc vs. the 70/30 copper zinc will not weigh the same for the same case volume. Next we need to ask ourselves how much it matters? A few years abck I got several thousand of the WCC 10 brass and it has really performed well. All of the above brass was once fired. Case volume was calculated using tap water.

Bummer is I have a few hundred new Lapua in standard .308 Winchester and the Palma (small primer) but did not include them. I simply overlooked them at the time.

Ron

 

[AJC1]

I normally start with new brass through this process (Lapua)

This is my learning brass to tear up neck turning and get a solid process before wrecking the good stuff

 

[AJC1]

I played this game or as my wife calls them my little science experiments. So here is what I did. I randomly selected 10 cases each of Remington, Winchester, WCC 10, LC 13 and Federal. All of the brass was sized and trimmed to nominal. Every effort was made to get the best uniformity possible.

View attachment 988258

Modeling clay as used in glass bedding was used to plug primer pockets which is represented by the 1.8 grain tare weights. I hope to get this brass loaded and shot over the chronograph this spring summer. Something to note when doing stuff like this is manufacturers do not all use the same brass composition. I forget which is which but some are 80/20 and some are 70/30. The 80/20 copper zinc vs. the 70/30 copper zinc will not weigh the same for the same case volume. Next we need to ask ourselves how much it matters? A few years abck I got several thousand of the WCC 10 brass and it has really performed well. All of the above brass was once fired. Case volume was calculated using tap water.

Bummer is I have a few hundred new Lapua in standard .308 Winchester and the Palma (small primer) but did not include them. I simply overlooked them at the time.

Ron

I dont believe weight is useful to compare across brands but is very helpful to identifying outliers in the same headstamp. To compare brands volume may be useful but a load is developed for a certain volume. If your looking for a brass with a similar volume that data would be nice to have. Thanks for your data set. I was interested in putting mine in a skater graph but dont have a good program. Looked at buying office and now they want yearly dues...***

 

[TEXASJD]

This is my learning brass to tear up neck turning and get a solid process before wrecking the good stuff View attachment 988257

That's the right brass to start with, But even with it the last gun I did that with out of 100 I ended up with 30 choice cases. That being said to really see the difference in those little 1/2% 1% accuracy increases the gun have to be capable.

 

[Reloadron]

Looked at buying office and now they want yearly dues...***

To be honest my version of MS Office is 2010 and I got it through a work program for literally a few bucks. Anyway, something to think about is Open Office which is similar to MS Office but free. There is something for each of the MS software. I used Excel but in Open Office it would be Calc. Really good software and free all open source.

Anyway yes, doing little experiments is always interesting. Thanks for sharing your results. I need to get the brass I used loaded and see how much difference, if any, I get.

Ron

 

[JFrank]

So Bart ( from Barts Bullets) tests a lot as well as being one of the top short and long range competitor's in the country uses a chronoghaph to cull out brass that isn't consistent in performance.
I've not tried that simply because my setup isn't the best with a pro Chrono vs Labradar but any thoughts towards the merit in his system?

 

[AJC1]

So Bart ( from Barts Bullets) tests a lot as well as being one of the top short and long range competitor's in the country uses a chronoghaph to cull out brass that isn't consistent in performance.
I've not tried that simply because my setup isn't the best with a pro Chrono vs Labradar but any thoughts towards the merit in his system?

I chat with him on accurate shooter but he is the man and I'm just an overzealous nub. You really want a kick this is my first 308 by myself. Dad used to load everything for me and I was just a trigger jerk

 

[AJC1]

Prepped my Remmington brass and tracked 30 samples. Sized, trimmed debured, chambered and uniformed flash holes resulted in total weight reductions between 0-.8 grains. The most common was .3 and .4 grains. I will conduct volume tests before and after fired on a 166.3 case as it was the most common.

 

[murf]

manufacturers do not all use the same brass composition.

X-Ray Spectrometry of Cartridge Brass within AccurateShooter.com

murf

 

[AJC1]

X-Ray Spectrometry of Cartridge Brass within AccurateShooter.com

murf

I rarely if ever see data an comparisons of regular consumer grade brass. I am far from a high tech solution, but I thought maybe my journey might be enjoyable by others that were curious. The 223 brass chart on 6mmbr was the quasi inspiration for my adventure. I wish the same chart was provided for 308.
My range brass testing is showing much larger deviations, and if I could afford all new I would buy and test that. The brass hounds like me dont really have a data set so I'm providing.

 

[murf]

the parent case for the 6mm br is the 308 win. i don't think case manufacturers buy special brass for their 6mm br cases. so the supplied chart should be applicable to your 308 win cases (assumption here).

that said, i don't think case material content has a large affect on accuracy here.

murf

 

[Reloadron]

I rarely if ever see data an comparisons of regular consumer grade brass. I am far from a high tech solution, but I thought maybe my journey might be enjoyable by others that were curious. The 223 brass chart on 6mmbr was the quasi inspiration for my adventure. I wish the same chart was provided for 308.View attachment 988891
My range brass testing is showing much larger deviations, and if I could afford all new I would buy and test that. The brass hounds like me dont really have a data set so I'm providing.

Absolutely follow through with this. Some of my own little "science experiments" have been pretty rewarding ventures. What I need to do now is this summer or spring run the brass I used in my posted example and see how it shoots and run it over a chronograph. Anyway by all means you continue with the adventure.

Ron

 

[Reloadron]

X-Ray Spectrometry of Cartridge Brass within AccurateShooter.com

murf

Thanks murf and that is what I was getting at.

Good dope in that link.

Ron