I decided to check and see what my Redding BR-30 was capable of throwing Varget at. I always throw then trickle my Varget loads under 75 grain Hornady BTHP and 80 grain A-Max pills.

Here are the results of 20 throws. Tapped twice at the bottom then lift. I did not weigh and threw back in two throws because handle lift was very hard as grains were cut.

1-24.9
2-24.6
3-24.8
4-24.9
5-24.8
6-24.7
7-24.6
8-24.8
9-24.7
10-24.9
11-24.7
12-24.6
13-24.5
14-24.5
15-24.7
16-24.6
17-24.6
18-24.6
19-24.8
20-24.6

High 24.9
Low 24.5
Average 24.695

Under 75 grain BTHPs doing 2740 fps, .4 grain difference is about 45 fps and 2.5 inches at 500 yards.

Would like to see what other powder measures will do. Anyone want to try the same with a Lee Perfect?

You assume that a .4 grains equals 40 FPS every time. Maybe you should shoot these through a chrono against perfectly weighed out charges.

I think he's using quickload for that number.

Strap a cheap fishtank air pump to the powder tube of the BR30, it will tighten the spread significantly.



kind

Wait, what

For the vibration to settle the powder down.
And if you don't have one installed,, a baffle will do some good also,, or a 4" funnel with a piece of clear, soft, plastic tubing cut to about one inch above the metal part of the measure.
'Borg

The vibration of the pump motor will cause the propellant to flow more easily and more consistantly.  It prevents "bridging."

Attach the pump to the powder tower with cable ties.



kind

'Course, You could always get one of those battery powered thingambobs to do it
'Borg

Never heard that tip before, you are serious, right.  Same problem here with a RCBS uniflow.  How much could this spread be cut down?

mince

Be careful, the lubricant from the battery powered thingamabob may contaminate your powder.



kind

Your powder measure it tough enough,, you don't need no stinking lube.
'Borg

I heard Dillon was doing a limited production run on these...

I have been using this method for over 20 years.  The benefits are dependent upon the powder used.  All powders will benefit to one degree or another.



kind

Why isn't it blue?



kind

http://www.ericwesselman.com/DillonPowderMeasure/ here is one tune up for the DPM

http://www.co-ar15.com/forums/showthread.php?t=4606 here is another one for the DPM

If nobody chimes in, I'll have my Lee set up in about a month and I'll try it and post results here.

Won't the wife get ticked when she can't find it!

Not at all,, course if you're a girlieman, ask her to get you one for Christmas
Sorry,, couldn't resist
'Borg

Battery powered toys and aquarium pumps aside...

Here's a thought or two for ya... mainly cuz I've been curious about such things as of late:

Try running your sample (n) out to 30... long story made short, sample size (n) >=30 is kind of the agreed upon magic line dividing 'small samples' from 'large samples'.  Basically your run of the mill statistics based on a sample >=30 have a better chance of accurately describing the 'population' (all the charges you will ever throw at that setting) than they would @ 20... just as 20 is better than 10, 5, etc.

As such... I tend to look less at the E.S. of the sample, than I do at the standard deviation.  E.S. describes the sample, S.D. attempts to describe the population.  Based on the numbers from your sample, 95% of the charges thrown from that measure at that setting would be within +/- 2 SD, or between 24.7 (your average) minus 2(0.13) and 24.7 plus 2(0.13)... aka 24.44 - 24.96.  Nearly all (99.7%) would be within +/- 3 SD - 24.31 to 25.09gr.

Just for giggles (and because I've been meaning to do so anyways for a while), I'll throw some charges of Varget from my measures this afternoon/evening.  I've got a BR-30, a Lee PPM, a Harrell's Custom 90, a Uniflow, and a Dillon APM.  Not sure how many I'll actually get to, but it could prove interesting.  Sorry, no vibrating toys so I can't throw those in for comparison

Something that might be of interest to you... there was an article in Precision Shooting magazine a number of years (10?) back.  Basically the author spent the entire winter (and I gathered he was from 'up north', where they have *long* winters) testing what amounted to most of the field of powder measures available at the time - from Harrell's Premium Culver on down to Lee PPM and most in between.  Tested knocking, soft, hard, not at all, etc. etc. and then ran some stats on the results.  Long story made very short... they all worked about the same in the long run.  I purchased a copy of it from PS, I'll see if I can find it and give ya the article name in case you want to order it.  It's actually a pretty good read.

Monte

Nuk, eager to see your results.

I recently watched the Tubb/Sierra reloading video. In the video Tubb says he throws all of his charges out to the 600 yard line. After that, he trickles and weighs charges.

dammit

Spent the better part of an hour typing and formatting the data into the 'advanced' editor... only to have it friggin' barf and only display the formatting *codes*, not the actual tables and cells.

Not doing that again, sorry.

If you want the info, send me a PM with your email address; I'll send you the Excel workbook file.  I'm done screwing around trying to post useful data to this board with no attachments.

I_B,  Very informative and accurate post.  While I have not taken the time to do what you have the BR-30 I use is certainly no more accurate than yours!  For any stick powder I throw short and trickle up.  



Well done.

I'll attempt to post nuk's work.

More from nuk:

i_b's BR-30

Mean 24.695
Standard Error 0.028538985
Median 24.7
Mode 24.6
Standard Deviation 0.127630222
Sample Variance 0.016289474
Kurtosis -1.021911078
Skewness 0.271297345
Range 0.4
Minimum 24.5
Maximum 24.9
Sum 493.9
Count 20
Confidence Level (95.0%) 0.059732783
"Sample Size (n)" 20
Average 24.7
High 24.9
Low 24.5
E.S. 0.4
S.D. 0.13
"Theoretical E.S. (6x StDev):" 0.78
"95% Confidence Level for Avg" +/- 0.06 24.64-24.76
+/- 1 SD (68.3%) 24.57-24.83
+/- 2 SD (95%) 24.44-24.96
+/- 3 SD (99.7%) 24.31-25.09


Lee PPM

Mean 24.478
Standard Error 0.021038552
Median 24.48
Mode 24.42
Standard Deviation 0.115232898
Sample Variance 0.013278621
Kurtosis 0.197872757
Skewness 0.60804877
Range 0.48
Minimum 24.3
Maximum 24.78
Sum 734.34
Count 30
Confidence Level (95.0%) 0.04302867
"Sample Size (n)" 30
Average 24.48
High 24.78
Low 24.30
E.S. 0.48
S.D. 0.12
"Theoretical E.S. (6x StDev):" 0.72
"95% Confidence Level for Avg" +/- 0.04 24.44-24.52
+/- 1 SD (68.3%) 24.36-24.6
+/- 2 SD (95%) 24.24-24.72
+/- 3 SD (99.7%) 24.12-24.84




Harrell's 90

Mean 24.458
Standard Error 0.013055144
Median 24.46
Mode 24.52
Standard Deviation 0.071505968
Sample Variance 0.005113103
Kurtosis -0.576331364
Skewness -0.091964016
Range 0.3
Minimum 24.3
Maximum2 4.6
Sum 733.74
Count 30
Confidence Level (95.0%) 0.026700767
"Sample Size (n)" 30
Average 24.46
High 24.60
Low 24.30
E.S. 0.30
S.D. 0.07
"Theoretical E.S. (6x StDev):" 0.42
"95% Confidence Level for Avg" +/- 0.03 24.43-24.49
+/- 1 SD (68.3%) 24.39-24.53
+/- 2 SD (95%) 24.32-24.6
+/- 3 SD (99.7%) 24.25-24.67



BR-30

Mean 24.39266667
Standard Error 0.013059839
Median 24.41
Mode 24.42
Standard Deviation 0.071531683
Sample Variance 0.005116782
Kurtosis -0.433343344
Skewness -0.414633729
Range 0.26
Minimum 24.24
Maximum 24.5
Sum 731.78
Count 30
Confidence Level (95.0%) 0.026710369
"Sample Size (n)" 30
Average 24.39
High 24.50
Low 24.24
E.S. 0.26
S.D. 0.07
"Theoretical E.S. (6x StDev):" 0.42
"95% Confidence Level for Avg" +/- 0.03 24.36-24.42
+/- 1 SD (68.3%) 24.32-24.46
+/- 2 SD (95%) 24.25-24.53
+/- 3 SD (99.7%) 24.18-24.6



Chargemaster

Mean 24.47266667
Standard Error 0.009941592
Median 24.48
Mode 24.42
Standard Deviation 0.054452341
Sample Variance 0.002965057
Kurtosis -0.755504414
Skewness -0.045872044
Range 0.2
Minimum 24.36
Maximum 24.56
Sum 734.18
Count 30
Confidence Level (95.0%) 0.020332838
"Sample Size (n)" 30
Average 24.47
High 24.56
Low 24.36
E.S. 0.20
S.D. 0.05
"Theoretical E.S. (6x StDev):" 0.3
"95% Confidence Level for Avg" +/- 0.02 24.45-24.49
+/- 1 SD (68.3%) 24.42-24.52
+/- 2 SD (95%) 24.37-24.57
+/- 3 SD (99.7%) 24.32-24.62

hmm

Guys,

Disregard most of the stuff above 'Sample size (n)' in each section... it was a block generated by M$ Excel's 'Descriptive Statistics' feature in their free Analysis Toolpack add-in.  I had it in the worksheets mainly as a check on my formulas.  The rest of the stuff is rounded down to two decimal places... no point in going out to 6 or 7 for this, IMO.  Things like mode, median, variance, sum, kurtosis, & skewness don't really matter for our purposes here.

After the fact I realized there may be a little confusion over the 95% confidence interval vs. the +/- 2 SD / 95% values.  Best as I can explain it in basic terms is thus:

The average (mean) for the given sample is a statistic we can calculate directly.  Without knowing all the values in the *population* (all the charges you might ever toss from that measure at that setting), we can't say for absolute certain that the sample mean is the same as the population mean.  They should be close, however, and how close is measured by the 'standard error' - basically like standard deviation, but for the mean.  Just as +/- 2 SD should contain 95% of the population, +/- 2 SE should contain 95% of the possible values for the mean.  Or, in simpler terms, we can say with 95% confidence that the population mean should be somewhere between +/- 2 standard errors.  If you wanted to be able to describe the population mean with 99.7% confidence, it would be +/- 3 standard errors.  Clear as mud, right?  Basically when you try to move from describing just what you measure (our samples) to using those numbers to predict future results, things get a little... fuzzy.  Bigger samples, and better measurements allow you predict things more accurately.

Otherwise... if you look at the S.D. number, take it times 2... the mean (average) plus or minus that value is about what you can normally expect 95% of the time from these powder measures given the sample data we have here.  My BR-30 did more or less the same as my Harrell's... but it has a number of 'upgrades', it's about 8yrs old and well broken in, and I have many thousands of cycles experience running it (which does matter).  I can't tell you how long innocent_bystander has had his BR-30, or how much he's used it.  Technique (specifically consistency) does matter a lot with these units - it probably relates back to the powder settling effect that others use the vibratory devices for.  The Chargemaster is plus or minus 0.1gr, 95% of the time.  The Harrell's and BR-30 should be +/- 0.14-0.15gr 95% of the time, assuming proper technique, etc.  The little Lee PPM... might have just been having a bad day?  Still, +/- 0.24-.25gr isn't bad for $20, and Varget is notorious for metering like crap, even among short-cut extruded powders.  The biggest use I have for the Lee anymore is to quick-throw a charge 0.3-0.5gr light into the pan on my Chargemaster, and use the electronic dispenser to top it off accurately.

I admit, I *am* curious as to how the vibratory action would affect the values of different measures.  I know a lot of people swear by them, but to be blunt, nobody using one has put up any numbers from an accurate scale to prove it.  I'm thinking about trying it, but seeing as how my Acculab scale and my Dillon 550 are mounted on the same bench, I'm thinking the vibratory action would drive the Acculab bat-$hit

Monte

My Harrel is +/- .1 grain as long as I don't knock it on the upstroke. If I knock it, I throw it back in.

YMMV.

Sure.  It's possible.  But I think I showed above that even with charges that all read 24.5gr exactly on a scale rated for 0.1gr ain't gonna be +/- 0.1gr all the time.  And now you're telling me that your powder measure throws +/- 0.1gr 'all the time'... on a scale that only reads +/- 0.1gr 95% of the time (unless you have an AccuLab or DI scale hidden away that you didn't mention).  See the problem?

In the end, all that *really* matters is if you are happy with the way it works, and the way your guns shoots.  If it works, it works,  and statistics be damned

I compete in High Power and I weigh EVERY FREAKIN charge. As long as I don't bump it on the upstroke I'm getting +/- 0.1 grains EVERY TIME for the past 6 years that I have owned my Harrel premium at approximately 7000 rounds loaded a year for .223. If I bump the upstroke, no such luck. I have no idea how he performed his experiment. For all I know the bumped the upstroke half the time and that will make a big difference.

YMMV. I don't feel like arguing what I know as FACT.

A.  cool the attitude.  I didn't say it was 'impossible'.
B.  Nobody is disputing your shooting credentials.  If you want to brag, I'm sure we can compare notes.  Get over yourself.
C.  I'm not saying that your charges don't read exactly as you describe... +/- 0.1gr on your scale.  My *point*, which you might have seen if you hadn't gone off half-cocked, was that most consumer reloading scales are barely that accurate to begin with.  It's what most people have to work with though, and works pretty well most of the time.  But I think if you measured your throws across a better scale, you might see some different results - regardless of your technique.

Go to the range man, do a couple RF strings and cool off.  You'll feel better.

RCBS Uniflow, CAPD on RL550B

"Sample Size (n)" 30
Average 24.03
High 24.26
Low 23.88
E.S. 0.38
S.D. 0.10
"Theoretical E.S. (6x StDev):" 0.60
"95% Confidence Level for Avg" +/- 0.04 23.99-24.07
+/- 1 SD (68.3%) 23.93-24.13
+/- 2 SD (95%) 23.83-24.23
+/- 3 SD (99.7%) 23.73-24.33

I loaded my #3BR powder measure with Varget.  Vibratory on, large micrometer in place.  Here is what I got for 30 throws:

3 X 25.4

9 X 25.5

13 X 25.6

2 X 25.7

3 X 25.8

Measurement were take with the scale of a Chargemaster 1500.  I am aware of the shortcomings of this measurement system, but it should be close enough for Gov'ment work.



kind

Vibrated powder throws

"Sample Size (n)" 30
Average 25.58
High 25.8
Low 25.4
E.S. 0.40
S.D. 0.11
"Theoretical E.S. (6x StDev):" 0.66
"95% Confidence Level for Avg" +/- 0.04 25.54-25.62
+/- 1 SD (68.3%) 25.47-25.69
+/- 2 SD (95%) 25.36-25.80
+/- 3 SD (99.7%) 25.25-25.91

Not bad...

Maybe I'm just lucky....but I polished my powder funnel with a dremel and flitz and I get no more than +/- .03 variance with the 650, as measured with 10 throws.


TR