Powder Measure Redux Part Four: Trickling in...
In our previous experiment we learned that even the best, most expensive powder measures suck at dispensing stick powders such as Varget.
On the other hand, Varget has a number of amazing characteristics such as temperature independence and a burning profile that is particularly suitable for high power
which make it indispensable component for long range shooters.
So how do we dispense it accurately?
The method that a lot of reloaders use is to throw a little bit less than the intended load, and then trickle the rest of the powder in using a powder trickler, directly into the
What kind of accuracy does this method yield? Since you are normally trickling it into a scale with the best resolution, you wouldn't know (beyond the resolution of that scale),
but with my super-accurate microbalance scale I could answer this question!
I did 15 measurements where I first dropped an underweight charge using a powder measure, and then trickled it to be
as accurate as I could on RCBS balance scale.
As you can see, standard deviation is roughly 0.027 (the first number is standard deviation of a sample; the second is
an estimate of the standard deviation of the technique itself - what would the standard deviation of an infinite series
of measurements be.
This means is that there is a 99.8% probability that the drop will be within 0.075 grain from an average - a pretty good