Pellet Rolling ~~ Part 3.

PART ONE

PART TWO

PART THREE

PART FOUR

PART FIVE



PLEASE NOTE: If there is anyone here who can show me that it is possible for two pellets having any difference in their external dimensions can roll on the same curve. I would greatly appreciate the information. I've been working on that for three days and I just keep proving it can't happen. There has to be something I am missing.



Summary to date:

If you want to bypass the reading there is a video here showing the machine



https://www.youtube.com/watch?v=M0LYlFFcAHQ



and a video here explaining the write up below.



https://www.youtube.com/watch?v=KLUvpbSzS1g





In part one I set up a test bed and a "rolling machine", selected the pellet to test, collected some data at 25 meters on my outdoor range, and proved the accuracy of the rifle used in the test was sufficient to measure any statistically significant improvement in group size. At the end of that series of targets I concluded that indoor testing would remove the "noise" of wind drift and scheduled a session at the "basement", which is a 25 yard indoor range to which I have access.

In part two I shot test groups and collected data which led to results which clearly indicated I was not measuring any statistically significant improvement in the test groups relative to the control group and again PROVED the accuracy of the rifle used in the test is sufficient to measure any statistically significant change in group size. The data showed no statistically significant improvement in the test groups. I established the "rolling machine" did indeed sort pellets by some criteria and there was discussion of what that might be but no conclusive proof of what characteristic of the pellet was indeed being sorted by the machine. The question was asked, "What exactly are we measuring?" The quality of the test machine was questioned and I resolved to rebuild the machine to improve selectivity.

In this part I answer the question, "What does the machine discriminate upon?". I have studied the machine. After all if we don't know what we are measuring, the result always will be meaningless. To that end I collected the following data:



Test One ~~ Does the new machine work?

I rebuilt the test machine and increased the number of "cells" in the catch box of the machine to 15 with the hope of improving its selectivity. I chose pellets which were already sorted on the first machine and fell into group #1 (the most central group). I rolled 75 of those pellets on the new machine. I observed a normal curve. This proves the test machine is sorting something. The question though is "why do pellets which have already been sorted once, fall into a normal curve on the new machine?" Part of the answer to that question is obvious. There are more cells in the new catch box and they are narrower, naturally they will be separated more. That was the objective, higher selectivity. But the distance across which they spread was significantly larger than the original cell into which they were sorted. Here is a page of notes I took at that time:

1.1627739603.jpg




Test Two ~~ How accurate is the machine?

Clearly something was amiss and a theory emerged. I decided to roll the same pellet 30 times to discover how the rolling machine was performing. I selected one at random from the original test sort #1. It rolled "long" about a third of the time but again we see in my note page that a normal curve was forming. That single pellet did not consistently land in the same cell? Here are the notes I took on that test.

2.1627740224.jpg


I was not happy with the fact that the pellet under test above fell past the catch box so many times and so ran that test again with a different pellet from test group #1. I selected the new pellet in order to ensure it fell towards the middle of the catch box. I then rolled that pellet 30 times. This I did because I wanted to confirm the above result. The pellet fell into four different cells in this test in what appears to be a normal curve. Here is that page of notes:

3.1627740477.jpg




Test Three ~~ Is there a problem with the catch box?

These results prompted me to replace the 15 cell catch box which was 10mm high with a 5 cell catch box which was 20 mm high. I did this to reduce the fall distance from the edge of the rolling table to the top of the catch box. I surmised the scattering I observed might be due to that drop. At this point I needed to establish a new control because I had again changed the machine. Using all the pellets from test group #1 (the original sorted group) I rolled 97 pellets into the new catch box. NOTE: These pellets were already sorted once on the first iteration of the machine. They should be similar. I kept notes and here is that page of notes. You will observe that ~50% of those pellets fell into cell number #2 and ~40% of those fell into cell #3. This gives us two new sorted groups, one of 49 pellets named 1-2 and one of 41 pellets 1-3.

4.1627741176.jpg




Test Four ~~ Lets sort pellets we have already sorted (BECAUSE SCIENCE, RIGHT?)

So I selected the pellets from group 1-2 which have now been sorted twice. Once on the original machine and once on this exact setup. We want to know if the machine really is sorting pellets. They should all fall into the same cell they fell into above. This will give us an idea how well we are actually sorting pellets. Here is the result of that test.

5.1627742120.jpg


What do you know? Pellets which, by all which is reasonable, should have fallen into cell number 2 instead fell into TWO cells. How can this be?



Test Five ~~ Lets do that again, we like punishment, master

So I collected the pellets and called that group 1-2-2. That means the pellets I am about to roll have been sorted three times and three times all of these pellets have landed in the same group:

6.1627742380.jpg


My, my, isn't that interesting?



Test six ~~ Hit me beat me, make me feel cheap

Let's roll a single pellet which has fallen into the same cell four (4), that's FOUR, times in a row. Let's to that 30 times just to make sure we have a REASONABLE statistical sample.

Does it fall into the same cell every time?

7.1627742595.jpg


Nope, master, I am a pathetic worm. I have failed.



Test seven ~~ Did you learn how to roll the pellet before you decided to use the machine?

It turns out that is a fair question. If you didn't, you were measuring how consistently you could roll a pellet... That's what this test measures as configured and commonly done. If you didn't take the time to LEARN how to put the same pellet in the same hole almost every time you were simply classifying pellets based upon how well you could roll them. To get valid data with this test machine a MECHANICAL release mechanism is almost mandatory.

Here is your sign (for those of you who have made up your minds already... and I don't mean YOU)

91.1627743268.jpg


More will follow and be linked here when it does.

Have a truly beautiful day. :)
 
admire your dedication to this topic

some of the results when rolling the same pellet have some interesting findings for this sample test

it is very difficult to build a jig or roll a single pellet the EXACT SAME WAY ALL THE TIME 

a lot of folks at the second from the highest level of accuracy needs will benefit from this approach

( and I did not mean you or a group of shooters like the phrase you people)

you probably can make and sell a fixture for this with moderate success, and I would buy one ( to resell to a newbie?)

it does help the discussion on this method of sorting pellets



comments on shooting will be left for another discussion 

at least you are trying and partially succeeding at getting more information out about this method and for that I thank you
 
[...]

a lot of folks at the second from the highest level of accuracy needs will benefit from this approach

[...]

you probably can make and sell a fixture for this with moderate success, and I would buy one ( to resell to a newbie?)

I would not be interested in trying to market something like you are describing. I suspect that something like a clothes pin would make a good mechanical release.

The real value here IF AND ONLY IF the method actually works would be to anyone who could show ownership of the test method. Manufacturers would obviously be very interested in a means of sorting pellets by machine and thereby improving their products. The "good pellets" that I believe @thomasair mentioned. I know what he was talking about. I always find "good" pellets too. They shoot so good in my HW98 that there is no point in trying to use them as the test pellet here.

I don't have any reputation for knowing what I am talking about and I don't compete with the elites. I am just another one of the unwashed and I certainly couldn't compete in any tier second, third, fourth, or whatever ... I wouldn't even be interested TBH. I shot my last bench match in '83 in San Angelo. I was shooting my H&A .54 cal underhammer at 200 yards. one hundred and ten (110)grains of Pyrodex RS and a 230 grain "well leathern ball" (see James Fenimore Cooper if the reference escapes you). I won that match. Pretty sure all you first tier shooters can shoot smaller groups than that thing could.

Whatever... I have some parts I need to draw up today. I'll be on that.
 
The tilt on your assembly seems excessive and your roll is very short.

When I roll mine they roll near nine inches and a full 90 degree arc. They are lined up on the glass against the thin piece of tape on the top ruler to start their journey. That is not to say this is any better than your way of doing it just a bit different.

The rolling does help sort the pellets with slightly damaged skirts and different ratio of head to skirt size. This does help with a more consistent poi and my gun seems to like a couple of the sorted pellets slightly more than others.

The pellets, on the glass, are not grouped according to where they landed, on the left ruler, but to where the groups ended up in general on the ruler. Most, nearly all, pellets end up between the six and nine inch marks on the left ruler.

I roll each pellet at least twice and some three times to be sure of consistency.


 
The tilt on your assembly seems excessive and your roll is very short.

When I roll mine they roll near nine inches and a full 90 degree arc. They were lined up on the glass against the thin piece of tape on the top ruler to start their journey.

The rolling does help sort the pellets with slightly damaged skirts and different ratio of head to skirt size. This does help with a more consistent poi and my gun seems to like a couple of the sorted pellets slightly more than others.

The pellets, on the glass, are not grouped according to where they landed, on the left ruler, but to where the groups ended up in general on the ruler. Most, nearly all, pellets end up between the six and nine inch marks on the left ruler.

I rolled each pellet at least twice and some three times to be sure of consistency.



Dude, you are talking heresy here, be careful. This test doesn't work and you are wasting your time. I have it on enormously reliable authority that is the case. However, I do like your thinking. I'm redrawing the parts today and will print them this evening. Then maybe next Wed I can reserve the "basement" and test the results. Before I even think about that I am going to ensure that I am able to differentiate between pellets with a high degree of confidence.

If we are lucky maybe I will be able to help you reduce the number of times you have to roll each pellet. That would be nice.

I really appreciate the advice. I think you are right. My slope was 1/12 and I think that is much too steep. I am going to go with something like about 1/25 for the next setup, maybe less. Do you know what the slope is in your setup? It looks quite well thought out, sir. Sadly I can't seem to get those 20 cal. Baracudas to roll on a larger curve. Probably that "bearing" surface on the head of the pellet that @therealld mentioned. It is effectively a short pellet because that band is pretty far back from the nose. That and the caliber make it roll "short".
 
I tried to do things the best I could and it seems to make a slight difference in my Impact poi anyway. I have seen your other tests and they seem to show a slight change in poi between groups and a slightly better group than with out of the tin pellets. Not allot of change and not allot better mind you but still a little.

Very nice werq on the posts by the way.

I have no idea what the slope is. It is the amount my computer desk is out of level on the basement floor. ;^)

PS I am using JSB .22 and .25 pellets with this.
 
I tried to do things the best I could and it seems to make a slight difference in my Impact poi anyway. I have seen your other tests and they seem to show a slight change in poi between groups and a slightly better group than with out of the tin pellets. Not allot of change and not allot better mind you but still a little.

Very nice werq on the posts by the way.

I have no idea what the slope is. It is the amount my computer desk is out of level on the basement floor. ;^)

PS I am using JSB .22 and .25 pellets with this.


Yes sir, there is something under the data I reported for part 2. The POI did move a bit and all average of the test groups was a few percent smaller. There is something being tested with respect to the pellet I just have not managed to build a test platform which I could control with a high degree of reliability. Will it make a big difference? Really, at this point who knows? If I can reduce the influence of my fumble fingers by 90% we may be able to get good enough data to FINALLY call it "busted" or "not busted".

By the way, here is the profile of the edge piece I am going to print this afternoon. I am printing it at 50 microns so that will take more than 4 hours but I think that is the critical point where the error gets introduced. Thoughts?

edge-profile.1627756537.jpg

 
Whew!!!! Some folks appearvto have lots of extra time on their hands!! I am retired andvwouldnt go thru all this....oh well to each his own!!


Yes sir, I am blessed. I don't really have to do much. Generally if I need a little extra money I just find some "piece work" writing code for someone or working on the network. Sometimes I get a little additional income from designing specialty parts and printing them, then offering them into the HAM radio community for sale. I've got a couple of little designs for pellet tins on the forum here which are there for anyone to download.

Why am I doing this? Because I want to keep my mind sharp. It's like a muscle (in particular, in my case, some would say a gluteus maximus ;) If I don't keep using it, it will atrophy. I'm 70 so might as well give something back to the community that I can do while I can. I've always been good at this sort of "stuff". I'll be out of the way soon enough.
 
Whew!!!! Some folks appearvto have lots of extra time on their hands!! I am retired andvwouldnt go thru all this....oh well to each his own!!


Yes sir, I am blessed. I don't really have to do much. Generally if I need a little extra money I just find some "piece work" writing code for someone or working on the network. Sometimes I get a little additional income from designing specialty parts and printing them, then offering them into the HAM radio community for sale. I've got a couple of little designs for pellet tins on the forum here which are there for anyone to download.

Why am I doing this? Because I want to keep my mind sharp. It's like a muscle (in particular, in my case, some would say a gluteus maximus ;) If I don't keep using it, it will atrophy. I'm 70 so might as well give something back to the community that I can do while I can. I've always been good at this sort of "stuff". I'll be out of the way soon enough.

“Success is not final, failure is not fatal: it is the courage to continue that counts.” - Winston Churchill
 
on the road at the moment so i cant go in to this as much as id like to…..

my wife is an artist, and glass is always around. used a 12x12 piece. propped up on one end using a standard sharpie marker…. used a HF right angle ruler aligned with the left and top edges of theglass, secured with doubled sided taped (also supplied from the mrs’ stash…)

i started them at around the 6 inch mark and moved out towards the 12 inch as i prgoressed… wanted a 90 roll to the left so the ruler became my calibration point.

once they rolled consistently to 90 degrees, i marked that spot on the top ruler and stsrted rolling. i put the pellet on that mark and GENTLYpushed away and up with my thumb, the pellet eould roll as soon as my thumb cleared the pellet. made for a much more consistent “release’

where the pellet “landed” on the left/verical ruler is what i sorted it by. I grouped them by 1/4 inch increments. Id only use the 3 biggest groups that occurred

having the rolling platform too high and theyd skid way out to the right and well past 90 degrees skewing the measurement. too low and they wouldnt complete the arc… 

Ive thought of 3d printing parts of this rig, but now that I have a head size I may not…. 



And IMO if we really want to put this to bed forever, a consistent and repeatable rig AND technique has to be developed. One that I can use, and Cornpone too making my meaurements more aligned to his. 

and gotta say KUDOS to Cornpone for this effort! 






 
and gotta say KUDOS to Cornpone for this effort!

Yes, agree 100%. Although it started to have a Hiroo Onodo vibe to it, a while ago. Not sure if I should admire or feel pity for the determination/zeal/efforts. 

Edit: had to google it, bad memory, Teruo Nakamara was the name I was after.

🇺🇸 When I was five we lived on Guan. That was in '57. There were still soldiers in the hills at that time.

What an adventure that was. We lived in a quonset hut. One day I brought home a piglet I had picked up in the back yard, a wild piglet. The sow came home with me. I took the piglet to my mom. The sow wouldn't leave the back door till I gave her back her keiki. She never third to hurt me. Once I brought home a skull with a bullet hole in it. Mom didn't let me keep it. I didn't think that was right. Then there was the time I climbed down the cliff and crawled into a cave. ... Had to call EOD to come clean it out. There were monitor lizards and spiders as big as a dinner plate. Very cool place for a five year old boy.

We will get past this. 🖖

I call it the "Internet Effect".Next time you see a meeting of people in the House of Representatives while debate is going on, look at the other people in the room. They are all on their phones, getting the information that the "AI" decides they want to see. They aren't listening to each other just talking past each other. We all do it (except perhaps me ;) ) Naw, we ALL do it and we do it ALL the time. I think it is really damaging our society, but I get caught up in it all the time. Those who would divide us, know this and exploit it.

But that topic is better discussed in person or in another venue, which is refreshing, actually. We are just here to do BB gun stuff.

I'm good. Sorry to have been so blunt.
 
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This part of the test is about over I think.

I am still working on building a pellet roller that has a low error rate. The best I have been able to accomplish releasing them by hand is an 8% error rate. The new machine has a slope of 1/25 vice 1/12. The pellets do roll further and do complete a full 90 degrees of rotation before they hit the box. I do believe that has helped a lot in improving the error rate, probably 50%. That would mean the error rate which was around 30% would be cut to 15% by simply getting the slope as small as you can (and still get the pellets to roll) and the distance traveled to be as much as you can. The rulers on a 12x12 of glass resting upon erasers at one end is just about perfect as far as slope and roll are concerned. The new box has 11 cells which are 12mm wide with a 1mm space between cells.

Anyone wishing to test their error rate to compare it with mine can simply mark off their rule in half inch lengths and try to roll the same pellet into the same half inch thirty times in a row, your error rate is 3.3 times the number of misses. If you hit the line it is a MISS. I averaged a number of tries to get that 8% number. If you test your error rate, please post it here. It may be that I am the only one who ever had that problem... :(

I am still printing parts and hope to complete the machine build tonight. If I can get an error rate below 5 percent I will move to the next part of the experiment.

That's where we are.

I hope everyone is having a good weekend.

Say your prayers. :) It can't hurt.