Powder throw variations

[Pancho Villa]

Hello,

I have an RCBS powder thrower, along with their scale. Throwing powder loads out I find that they are varying by up to 3/10ths of a grain. How much would that affect consistency? Is this normal? How do I prevent this variation, if there is a way? Using 2025 powder, if that helps. Here is my load data for 20 measured throws:

(because I lack a chronograph I am aiming for the low-end of the scale. Sierra recommends 36.9 grains as a minimum for loading their 168gr BTHP.)

37.3: 6
37.2: 5
37.1: 3
37.0: 6

There are 5 consistent groups within the 20 loads, where 2 (3, one time) consecutive loads are the same weight.

[Pancho Villa]

Update: The last 18 throws have varied by only 1/10th of a grain (37.2 or 37.3) with one exception (37.0.) The last 6 throws have all been 37.3 grains exactly.

[gnihcraes]

I'm not familiar with that powder, but this seems about normal to me. Different powders measure differently in the powder dispenser. The pistol ball or flake powders throw very consistent in mine, but the rifle powders vary a little more. If you're not doing many loads and want to be precise, measure them by hand. I usually check several times the weight being thrown each 50 rounds I do. check the first one, check the last one in each 50.

[LariatBob]

Are you talking about the Chargemaster 1500?
I have heard about some variations, but mine always weighs within 1/10 when checking on another scale.
I read somewhere to get a large drinking straw (McDonalds?) that will slip over the dispenser tube. Cut it so it sticks out about 3/8". Supposedly that helps the powder trickle out more consistantly and helps a bunch.
Haven't tried it myself, please let me know what you find if you do.