H20 Brass Weighing...The Truth...or somewhere in that range.

[Dave Berg]

The meniscus as you call it. What is the benefit/purpose? Why would Quickload require measurements like that? It would seem to me that this would give a false high. We can't fill powder past the case mouth. It would also be harder to control. I find a single drop of water is about 0.5 grains.

I call it the meniscus because that's how it's known in the scientific world. Everyone who works in the chemistry field deals with it all day every day. Burettes, pipettes, barometers (real ones with mercury) all have a meniscus that must be considered. Burettes and pipettes with water based solutions have a concave meniscus (higher next to the glass than in the center). These are always read at the bottom. A mercury barometer has a convex meniscus which is read at the top. It's just the way life is.

If one drop weighs 0.5 grains you need a smaller dropper. A fine hypodermic needle with appropriate syringe produces very small drops. They can be somewhat hard to come by. I have a couple I got 40 or more years ago that were for insulin injections and a couple newer ones that a veterinarian friend gave me. Really tiny drops.

I don't know why the Quickload folks decided on filled to overflow. However, in my experience as a research chemist that's what I would have chosen as it's the most repeatable. It does take a bit of getting used to, aka practice, to fill it until just before it runs over. Much like the plumber tightening something until just before it breaks. Since Quickload was developed while the author was getting his PhD he may have felt the same way.

 

[Joe R]

This is starting to confirm what I've heard before. Brass produces the lowest ES on first firing.

Jimmy,
I respectfully disagree. Here is the print out on two strings that I did today while developing a load for a new bullet. The brass has been fired 3 times and I get good SDs and ESs (5 or better most times) by annealing and watching my neck tension (21st Century hydro press). The T= extreme spread, the $= std dev.

Erik Cortina taught me the Holy Trinity of precision reloading:

1. Powder
2. Neck tension
3. Seating depth

Think of it as a 3 legged stool, if one is out of balance the stool is crooked. You've resolved the powder issues by getting yourself a good scale, the seating depth is easy enough to figure out once you get the neck tension issues resolved. That's a tough nut to crack because you have to play with precision to the 10,000th of an inch. Not easy but very doable. Get yourself a good micrometer (.00001 precision) and you'll nail it soon enough.

Kindest regards,

Joe

 

[Sheldon N]

Done.
Lightest 11: Avg = 2659.273 / Heaviest 10: Avg = 2661 / FPS diffeerence 1.727

Threw out the outliers both which occurred in the heaviest 10.

Lightest 9: Avg = 2657 / Heaviest: 10: Avg = 2667.1 / FPS difference 10.1

There was a large ES. On the second set of averages I threw out the slowest and fastest chrono reading. I believe the second set of data may be slightly more accurate.

Nice work! I agree the outliers are likely neck tension variances. I'm not quite sure I understand how you calculated the revised averages though. Where were the outliers? In the heavy or the lightest set?

With highly variable data I might suggest dropping the top two and bottom two readings from both the high/low data set and then just averaging the middle 5-6 values, like an average/median. That will probably get you as close as possible to the true fps attributable to the volume change.

Also, can your provide the average case volume for the two data sets? I'm curious how well the actual data tracked with Quickload's predictions in terms of fps vs case capacity in 0.1g increments.

 

[DBailey]

Get yourself a good micrometer (.00001 precision) and you'll nail it soon enough.

Kindest regards,

Joe

.0001

 

[Mozella]

......... snip.......... That's a tough nut to crack because you have to play with precision to the 10,000th of an inch. Not easy but very doable. Get yourself a good micrometer (.00001 precision) and you'll nail it soon enough.

Kindest regards,

Joe

Not only a tough nut to crack but an expensive one as well. I found a nice micrometer which will meet your precision recommendations, but it costs $1100. I think I'll pass.

 

[Endyo]

I call it the meniscus because that's how it's known in the scientific world. Everyone who works in the chemistry field deals with it all day every day."...

Thanks Dave, That makes a lot of sense. As handloaders we are jacks of all trades. It only makes sense that someone with a scientific background would integrate lab techniques such as those you mentioned. Heck my scale is a scientific scale.

I'll definitely make changes to my technique as you suggested and monitor for consistency.

On that same note I don't know the best statistical techniques for averaging data with such a drastic ES. I don't trust the accuracy of this data due to faults in other areas of my handloading capabilities.

Attached below is the raw data. Whatever comparisons need to be drawn can be derived from this data. I sorted velocity from low to high and data was sorted this way not by case volume. I hope this helps.

 

[Sheldon N]

Thanks! That's perfect. Having the individual velocities matched to each case capacity is actually way more helpful than just an average of two lots. I've parsed some of the data for you.

First, let's just run a scatter plot showing the capacity vs velocity with a trend line.

You can see in the scatter plot that there are two or three clear velocity outliers that fall well outside the trend. Two are low velocity rounds that were "mid pack" for capacity. There's also one, less severe, high velocity outlier that was on a lower capacity case. However, even with those outliers the trend line appears quite clear.

If you parse it by average velocity, dividing into a "low volume" lot and a "high volume" lot you can also calculate an average difference. I would lean towards tossing those two low velocity rounds out of the data set (There's one in each lot). With the remaining 19 cases divided into two lots, you get the following...

Big Lot
Avg Volume 67.85g
Avg Velocity 2667.7fps

Small Lot
Avg Volume 67.61g
Avg Velocity 2662fps

So we've got about 0.2g of capacity difference equating to 5-6fps velocity difference, bigger capacity going faster.

Now let's look at standard deviation of velocity, which is what we're really after here. Again, we'll toss out the two low velocity outliers.

Std Dev of all 19 Cases: 13.17 fps
Std Dev of Big Lot: 12.2 fps
Std Dev of Small Lot: 14.3fps

There's another thing that's confusing me.... Quickload would predict that a higher volume case given the same amount of powder, will be slower than a smaller volume case. That makes common sense too... the small volume case is going to have a higher initial pressure and a higher velocity as a result. The trouble is, your results are the opposite...

So I don't know what to make of it all... the velocity differences are not what we'd expect, so there's got to be some other factor at work here. Perhaps neck tension that tracks with case volume and the thickness of brass? Perhaps certain powders react more favorably to extra volume and generate more velocity?

I think for me the two lessons are this...

1) Sorting brass by volume doesn't seem to improve standard deviation of velocity.
2) There seem to be bigger factors at work that drive standard deviation, beyond case capacity.

Again, I appreciate the extra effort you've put into doing all this. Even if the net result wasn't necessarily what was hoped for, it's a great learning exercise and hopefully valuable to others here at the forum.

 

[savagedasher]

Thanks! That's perfect. Having the individual velocities matched to each case capacity is actually way more helpful than just an average of two lots. I've parsed some of the data for you.

First, let's just run a scatter plot showing the capacity vs velocity with a trend line.

You can see in the scatter plot that there are two or three clear velocity outliers that fall well outside the trend. Two are low velocity rounds that were "mid pack" for capacity. There's also one, less severe, high velocity outlier that was on a lower capacity case. However, even with those outliers the trend line appears quite clear.

If you parse it by average velocity, dividing into a "low volume" lot and a "high volume" lot you can also calculate an average difference. I would lean towards tossing those two low velocity rounds out of the data set (There's one in each lot). With the remaining 19 cases divided into two lots, you get the following...

Big Lot
Avg Volume 67.85g
Avg Velocity 2667.7fps

Small Lot
Avg Volume 67.61g
Avg Velocity 2662fps

So we've got about 0.2g of capacity difference equating to 5-6fps velocity difference, bigger capacity going faster.

Now let's look at standard deviation of velocity, which is what we're really after here. Again, we'll toss out the two low velocity outliers.

Std Dev of all 19 Cases: 13.17 fps
Std Dev of Big Lot: 12.2 fps
Std Dev of Small Lot: 14.3fps

There's another thing that's confusing me.... Quickload would predict that a higher volume case given the same amount of powder, will be slower than a smaller volume case. That makes common sense too... the small volume case is going to have a higher initial pressure and a higher velocity as a result. The trouble is, your results are the opposite...

So I don't know what to make of it all... the velocity differences are not what we'd expect, so there's got to be some other factor at work here. Perhaps neck tension that tracks with case volume and the thickness of brass? Perhaps certain powders react more favorably to extra volume and generate more velocity?

I think for me the two lessons are this...

1) Sorting brass by volume doesn't seem to improve standard deviation of velocity.
2) There seem to be bigger factors at work that drive standard deviation, beyond case capacity. Looks like CCI primers

Again, I appreciate the extra effort you've put into doing all this. Even if the net result wasn't necessarily what was hoped for, it's a great learning exercise and hopefully valuable to others here at the forum.

Where did you get the brass? I would like to get some . I never found your results . The deviation your getting is primers . I see the results you give Doesn't mean a lot . Next chance primers and make sure of the powder drop . Larry

 

[Endyo]

The Hornady brass came with a rifle I purchased on these forums as a package deal. It came with a lot of extras.

I've done primer tests in the past but until the numbers get lower it's very difficult to determine which variable is causing the variation in velocity.

The primers are CCI BR-2.

Powder drop is down to +/- 0.02 grains. That's about one kernel of powder. I won't be able to weigh more precisely unless I get a $1,000 scale or a Prometheus.

I am disappointed that the more precise powder drop didn't seem to improve my ES. I think my numbers were actually worse. I was shooting a light load. I wonder if the change in case fill caused changes in pressure and ultimately fps.

 

[savagedasher]

The Hornady brass came with a rifle I purchased on these forums as a package deal. It came with a lot of extras.

I've done primer tests in the past but until the numbers get lower it's very difficult to determine which variable is causing the variation in velocity.

The primers are CCI BR-2.

Powder drop is down to +/- 0.02 grains. That's about one kernel of powder. I won't be able to weigh more precisely unless I get a $1,000 scale or a Prometheus.

I am disappointed that the more precise powder drop didn't seem to improve my ES. I think my numbers were actually worse. I was shooting a light load. I wonder if the change in case fill caused changes in pressure and ultimately fps.

How did you do the case capacity something isn't lining up. Larry

 

[Endyo]

Thanks! That's perfect. Having the individual velocities matched to each case capacity is actually way more helpful than just an average of two lots. I've parsed some of the data for you.

First, let's just run a scatter plot showing the capacity vs velocity with a trend line.

You can see in the scatter plot that there are two or three clear velocity outliers that fall well outside the trend. Two are low velocity rounds that were "mid pack" for capacity. There's also one, less severe, high velocity outlier that was on a lower capacity case. However, even with those outliers the trend line appears quite clear.

If you parse it by average velocity, dividing into a "low volume" lot and a "high volume" lot you can also calculate an average difference. I would lean towards tossing those two low velocity rounds out of the data set (There's one in each lot). With the remaining 19 cases divided into two lots, you get the following...

Big Lot
Avg Volume 67.85g
Avg Velocity 2667.7fps

Small Lot
Avg Volume 67.61g
Avg Velocity 2662fps

So we've got about 0.2g of capacity difference equating to 5-6fps velocity difference, bigger capacity going faster.

Now let's look at standard deviation of velocity, which is what we're really after here. Again, we'll toss out the two low velocity outliers.

Std Dev of all 19 Cases: 13.17 fps
Std Dev of Big Lot: 12.2 fps
Std Dev of Small Lot: 14.3fps

There's another thing that's confusing me.... Quickload would predict that a higher volume case given the same amount of powder, will be slower than a smaller volume case. That makes common sense too... the small volume case is going to have a higher initial pressure and a higher velocity as a result. The trouble is, your results are the opposite...

So I don't know what to make of it all... the velocity differences are not what we'd expect, so there's got to be some other factor at work here. Perhaps neck tension that tracks with case volume and the thickness of brass? Perhaps certain powders react more favorably to extra volume and generate more velocity?

I think for me the two lessons are this...

1) Sorting brass by volume doesn't seem to improve standard deviation of velocity.
2) There seem to be bigger factors at work that drive standard deviation, beyond case capacity.

Again, I appreciate the extra effort you've put into doing all this. Even if the net result wasn't necessarily what was hoped for, it's a great learning exercise and hopefully valuable to others here at the forum.

Thank you for running the numbers Sheldon. The results were close to QL estimates...only inverse.

I've been wracking my brain trying to figure out why the data doesn't seem to make sense.

Thinking back on it I noticed some case mouths were not uniform so as a handloader I fixed the issue by running all the brass through the resizing die.

Running a test I should not have done this. I know now I changed the internal volume by doing this.

I'm still not sure if that explains the inverse function...

I have another set of brass and corresponding weight data. I'm going to try this one more time. This is the Hornady brass brand new and unsized. Ideally I should have sized before weighing. I guess I could size than re-weigh?

I'm willing to rerun the test. I would need input on the parameters as I obviously screwed up the last test...this is a little bit beyond the scope of my experience.

If there's still no correlation than at least we know it wasn't from human error.

 

[savagedasher]

Thank you for running the numbers Sheldon. The results were close to QL estimates...only inverse.

I've been wracking my brain trying to figure out why the data doesn't seem to make sense.

Thinking back on it I noticed some case mouths were not uniform so as a handloader I fixed the issue by running all the brass through the resizing die.

Running a test I should not have done this. I know now I changed the internal volume by doing this.

I'm still not sure if that explains the inverse function...

I have another set of brass and corresponding weight data. I'm going to try this one more time. This is the Hornady brass brand new and unsized. Ideally I should have sized before weighing. I guess I could size than re-weigh?

I'm willing to rerun the test. I would need input on the parameters as I obviously screwed up the last test...this is a little bit beyond the scope of my experience.

If there's still no correlation than at least we know it wasn't from human error.

I never check the capacity till the brass had been fired 2 times . Then I don't resize it . By the second reloading I have narrowed my primers choice . I also have also sorted the brass by crono speeds .Larry

 

[dmoran]

Tom
Besides what you said, what I don't get is how he's talking 6Dasher and Endyo is talking 284.....
D

 

[Sheldon N]

I have another set of brass and corresponding weight data. I'm going to try this one more time. This is the Hornady brass brand new and unsized. Ideally I should have sized before weighing. I guess I could size than re-weigh?

I'm willing to rerun the test. I would need input on the parameters as I obviously screwed up the last test...this is a little bit beyond the scope of my experience.

If there's still no correlation than at least we know it wasn't from human error.

I did go back and look at the info on the Hornady unfired brass and you have a good correlation between weight and volume.

If this is virgin, unfired brass from the same lot then I think you've got a good base for a test. Assuming that you've done no case prep or anything to them, my suggestion would be to do a little to the case as possible and just load and fire them. Consistent neck tension would be important so if you have an expander mandrel like the Sinclair Gen II mandrel that would be a good way to ensure nice round, evenly sized case necks.

In a perfect world it might be better with once fired or twice fired brass fully formed to your chamber, but then you also would need to ensure that your trim length was perfect along with all the other associated case prep like champfer/debur being exactly the same. Much simpler to just run with what you've already got.

If you can provide clean velocity data for each case along with weight and volume, I can give you the all the breakdown on correlation and to what extent weight sorting or volume sorting makes a difference in SD and velocity.

 

[Endyo]

Thank you again for crunching the numbers. The scatter charts make it easier to visualize the data.

The brass is primed with no other case prep done. I do have a Sinclair Expander mandrel I may consider taking this extra step to try and help with consistent neck tension.

I'll shoot the rounds and post the raw data hopefully later today.

 

[dmoran]

"... I do have a Sinclair Expander mandrel I may consider taking this extra step to try and help with consistent neck tension"

Good plan - I suggest you do, and feel it should/could help the ES.
Looking forward to seeing the results.

Interesting thread... Thanks
Donovan

 

[Endyo]

I ran a quick test:

Hornady (New).......(Sized)........Mandrel......Inside Diameter......ID after Mandrel.......Case length
1. 66.0gr................65.8gr.........65.82gr.......0.281-0.2815...........0.2815................2.152''
2. 65.92gr..............65.8gr.........65.76gr.......0.2805-0.2815.........0.2815................2.151"
3. 66.24gr..............65.76gr.......65.72gr.......0.281-0.282.............0.2815................2.151"

FINDINGS:
1. Full Length Sizing did it's job Very well! A MORE consistent Internal Volume was produced.

2. The Mandrel did it's job . It's yet to be seen if this will reduce ES/SD.
(Consistent ID is only one part of addressing Neck Tension.)

3. The Mandrel did not effect internal volume significantly.
The differences from the previous weighing may have been slight re-measuring errors.

4. This debunks my theory that sizing may have introduced variance on the previous test.

5. The value of internal volume weighing may be reduced if one full length sizes their brass.


Until I am able to produce single digit ES/SD. It will be difficult to determine how much brass weight or internal volume affect velocity since the changes seem to be small. The previous batch had a relatively small variance in internal volume and estimated changes were 5-10FPS. Yet that brass produced an ES of well over 70FPS over 21 rounds. This was after full length sizing which we found actually REDUCES variance between cases so overall velocity variance should have been significantly less than 5-10FPS.

With these findings I feel it's safe to predict that I have bigger issues elsewhere as previously discussed. Until I can address other arenas of my handloading (primarily neck tension at the moment) I am going to freeze any future tests with H2O weighing.

 

[dmoran]

Interesting report..... again Thanks for sharing !.!.!
Donovan

 

[Sheldon N]

Very cool info. Thanks again for sharing. Would love to see more results once you have time to resume your testing. Would love to try and extrapolate your data to see if there is merit in sorting brass cases by weight (a fairly common practice, compared to volume weighing) and if there would be any merit to sorting cases by velocity and comparing the subsequent firings.

 

[lbran]

The Hornady brass came with a rifle I purchased on these forums as a package deal. It came with a lot of extras.

I've done primer tests in the past but until the numbers get lower it's very difficult to determine which variable is causing the variation in velocity.

The primers are CCI BR-2.

Powder drop is down to +/- 0.02 grains. That's about one kernel of powder. I won't be able to weigh more precisely unless I get a $1,000 scale or a Prometheus.

I am disappointed that the more precise powder drop didn't seem to improve my ES. I think my numbers were actually worse. I was shooting a light load. I wonder if the change in case fill caused changes in pressure and ultimately fps.

try 210m primer!