Uniflow Powder Measure Experiments (lots-o-pictures)

[bergmen]

I reload all of my calibers (7 handgun, 5 rifle) using four Winchester powders (W231, W296, W748, W760). These are all ball powders and I have read where it is wise to use a baffle in the powder measure column or keep the column full to assure consistent measurements with a full column vs. nearly empty column.

Well, today I ran experiements to see if there is any difference between a full Uniflow powder column and a near empty one with all four powders.

First powder up is W748 since the last reloads I did was for .308 Winchester:

Powder scale is set up for 47.7 grains. I pour in just enough powder to be above the base casting. I will call this "W748-Low Measure Column":

Measured charge I call "W748-Low Measure Scale":

Then I fill the column to the top. "W748-High Measure Column":

"W748-High Measure Scale":

Next up is W760.

This powder measures lighter so I adjust the powder measure to throw about a 47.9 grain charge. "W760-Low Measure Column":

"W760-Low Measure Scale":

"W760-High Measure Column":

"W760-High Measure Scale":

No discernable difference between low column volume and high column volume for W748 or W760.

For the handgun powders I disassemble the Uniflow and install the small measuring ram. First powder is W231.

A common charge I throw for this powder is 5.0 grains so I set up the powder measure to throw a charge close to this (4.9 grains) using the "W231-Low Measure Column":

"W231-Low Measure Scale":

"W231-High Measure Column":

"W231-High Measure Scale":

(Continued next post)

 

[bergmen]

Chapter II

Last powder is W296:

A common charge I use for this powder is 20.0 grains so I set up the powder measure to throw a charge close to this (19.9 grains).

"W296-Low Measure Column":

"W296-Low Measure Scale":

"W296-High Measure Column":

"W296-High Measure Scale":

So, as you can see, I have no worries about the powder charges changing as the powder gets lower in the Uniflow. I would imagine, because of the results of this experiment, that I have no need for a powder baffle.

The only thing I have ever read in any of the manuals is not to do what I just did since the powder charges will vary from full column to nearly empty column. Along with this advice is no measured substantiation of their concerns. It looks like this is not an issue with the Uniflow and ball powders (at least the four I use).

Dan

 

[GTS Dean]

My experience is a lot different than yours. It got a lot better when I put in a powder baffle.

 

[ssyoumans]

I've never used one, ball powders for me are extremely consistent out of my RCBS Uniflow.

My problems are with sticks, Varget, and large flake, Unique.

 

[bergmen]

My experience is a lot different than yours. It got a lot better when I put in a powder baffle.

My experiment is very limited since I am only looking at four powders. There may indeed be differences with other powders. It would be interesting to see measured differences between low and high columns.

Dan

 

[cfullgraf]

I get better results with the powder baffle than without. I make sure that the opens in the baffle are not over the opening in the charge cavity. In other words, the line between the center of the two baffle holes is parallel with the rotational axis of the drum.

Others have good success without the baffle or with the baffle located higher in the reservoir.

 

[41 Mag]

I get about the same results as what you ahve posted out of all of mine.

I do find that with the thinner stick powders like IMR-3031 I get better results when I use the baffle.

For the most part however I usually have a piece of masking tape across the bottom with the powder type written on it. Once the powder gets to that level, I usually either fill it back up, or I am through and dump it out. Just my own way of keeping somewhat of a steady head on the reservoir.

 

[buckbrush]

all of the powders you tested measure very well, try H-4831 and some flake powders.

 

[Blue68f100]

It looks like you did not settle the powder when you filled it up to full. Once you throw about 20-40 drops you may get different results.

 

[atblis]

Did you throw/measure only one of each? If so, that's pretty much completely meaningless.

Record 100 of each thrown in exactly the same way you would if you were loading. Present that in a table. That would actually be meaningful/interesting.

 

[dickttx]

The only one you tested that I use is HP38. I get the same results as you did in my Lee Pro Auto Disk. I seldom load over a hundred rounds at a time, so I usually start with the measure about 3/4 full. If I load more rounds at that setting, I repleinish. I just pour the powder in and start loading without settling, banging, jiggling, etc. With fluffy flake powders or large stick powders the results might vary.

 

[JRH6856]

Did you throw/measure only one of each? If so, that's pretty much completely meaningless.

Record 100 of each thrown in exactly the same way you would if you were loading. Present that in a table. That would actually be meaningful/interesting.

+1

The expectation is that a full hopper gives more consistent results than a nearly empty one, not whether or not one random throw under each condition happens to match. My concern would not be whether one low and one high column load are the same, but whether multiple loads were consistent under changing conditions.

 

[bergmen]

Did you throw/measure only one of each? If so, that's pretty much completely meaningless.

Record 100 of each thrown in exactly the same way you would if you were loading. Present that in a table. That would actually be meaningful/interesting.

Admittedly I am only showing an example of one. To be statistically relevant I do need to present a full data sheet of many measurements.

But this is what I have seen over 20 years of reloading with these four powders. I always weigh the first charge with a full column even though I'm only going to load 50 rounds at 5.0 grains each. I always check at the end of the case charging phase (or at the lowest column volume that you see in the pictures). Never a difference.

I'm careful with my powder measuring, always have been. I've never had an over or under charged round in my entire reloading career (tens of thousands of rounds).

I've also never seen a variation in measured charge weight due to column level, I check it all the time.

But you are correct, I am not indicating in this experiment that I have experienced these same results for years.

Dan

 

[TonyT]

I cannot comment on the RCBS Uniflo measure as I have never used it wiith less than ca 1/4 full. Howver with my Dillon 550 and W-231, WST or Bullseye I can get very uniform pwder drops even when the powder chamber is almost exhausted and well below the baffle.

 

[mbopp]

I find W231 meters close with the hopper empty or full. But with Unique, Red Dot, or Bullseye I keep it above the baffle, my Redding #3 w/ the pistol measure throws progressively lighter charges if I let it go below the baffle.

 

[atblis]

Admittedly I am only showing an example of one. To be statistically relevant I do need to present a full data sheet of many measurements.

Yes you do. I don't know off hand how to design a meaningful experiment in this case (how many samples you'd to need for the results to be meaningful), but I am sure there those here who could tell you.

I like where you were going with this and would like to see the results.

http://en.wikipedia.org/wiki/Sample_size
http://en.wikipedia.org/wiki/Design_of_experiments

 

[bergmen]

Yes you do. I don't know off hand how to design a meaningful experiment in this case (how many samples you'd to need for the results to be meaningful), but I am sure there those here who could tell you.

I like where you were going with this and would like to see the results.

http://en.wikipedia.org/wiki/Sample_size
http://en.wikipedia.org/wiki/Design_of_experiments

Let me think about this for a bit. I am a Mechanical Engineer by profession and gathering data and producing test reports is SOP for me.

I'll want to do this for all four powders and be more concise on the measured charge thrown under defined and repeatable conditions. Ambient temperature should be one of the data points recorded as well.

Stay tuned, this could happen this weekend...

Dan

 

[Master Blaster]

I reject your reality and substitute my own. Many years of reloading and owning a Hornady LNL measure, two dillon measures, a Redding Benchrest and an old Lyman (with the three adjustibloe slides), and throwing many charges of different powder. Has shown me that a baffle is necessary in some of the measures, but not others.

So the answer is you have to test your measure with your powder. Your results would probably be a bit different after 20 or 30 throws as the powder settles, and for sure different with rod or flake powder.

 

[bergmen]

I reject your reality and substitute my own. Many years of reloading and owning a Hornady LNL measure, two dillon measures, a Redding Benchrest and an old Lyman (with the three adjustibloe slides), and throwing many charges of different powder. Has shown me that a baffle is necessary in some of the measures, but not others.

So the answer is you have to test your measure with your powder. Your results would probably be a bit different after 20 or 30 throws as the powder settles, and for sure different with rod or flake powder.

You can reject it if you want. My test was only with the four powders I listed and only with the RCBS Uniflow, not flake or rod powders or any other type of powder measure. In literally hundreds of reloading sessions with these four powders I have never seen any difference in charge weights due to any difference in quantity in the Uniflow powder measure. I never do anything but just pour powder into the column, I don't tap the sides to settle it, nothing.

I do need to report much more comprehensive test results rather than the single examples I report here, but I can assure you the results won't show any difference.

Dan

 

[AABEN]

When did Winchester start making w231 in ball powder? All that I have is flake.

 

[cfullgraf]

I believe W231 is what they call a "flattened ball" powder.

 

[cfullgraf]

If I understand the OP's original experiment, he added powder to the measure after getting his low level data. The powder directly above the metering chamber would still be settled.

So, the additional powder would add weigth to the column, but would not really affect the density for a few throws.

With my powder measures with baffles installed, I can run the powder down to the baffle without any effect on the charges thrown. I can add powder at any time and by the time the new powder has reached the metering chamber it has settled sufficiently. Again, no changes on the accuracy of what the measure throws.

 

[AABEN]

I jest look it up and on the new can it reads ball powder. On my old cans it does not it say ball powder. Thank

 

[bergmen]

When did Winchester start making w231 in ball powder? All that I have is flake.

It says "Powder" under the price sticker.

Dan

 

[AABEN]

All the powder that I have is in metal cans. You have the new