I have a RCBS Uniflow powder measure. I'm consistently getting variations of up to .2 grains on a drop. Anyone have any suggestions? Usually when testing the measure I drop about 5-6 times, put that back into the powder measure, and then measure the 7th drop after any adjustment.
Having issues getting a consistent powder drop
- Thread starter lord1234
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wyocarp
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Absolute perfection is hard to come by. You didn't mention what type of powder you are using, it will make a difference in how accurately they get dispensed. Personally, that is within the standard deviation for everyday shooting.
Is this for competition shooting? Do you weigh every bullet as well? Because they will vary more than that.
Is this for competition shooting? Do you weigh every bullet as well? Because they will vary more than that.
Yep, need to know what powder etc. 
.2 on a rifle charge? No worries.
.2 on a 4.0 Gr pistol charge? Not that great, but as good as some flake powders do.
When you first fill the powder reservoir, drop at least 10 charges to settle the powder. Then the way you are doing it is just fine. At least that is what I do anyway.
.2 on a rifle charge? No worries.
.2 on a 4.0 Gr pistol charge? Not that great, but as good as some flake powders do.
When you first fill the powder reservoir, drop at least 10 charges to settle the powder. Then the way you are doing it is just fine. At least that is what I do anyway.
AA #5, WSF, HS-6, or similar powder will work great in 9MM, and meter extremely well, but W-231 is very good in 9MM and should meter well enough. AA #2 will work for light loads in 9MM, and it meters like water.
Steve H
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do you have more than one scale? Maybe your powder thrower is ok but your scale is off.
wild willy
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Have you taken your measure apart and cleaned and degreased it. I had trouble once a bug or spider had a nest in the drop tube. 231 should meter very close it does in mine
Bula
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agreed w231 is one of the most consistent ball powders I've used. Make sure your scale is level, and a +1 on cleaning out the Uniflow.
You should be using the small 0 to 50 gr measuring cylinder and not the standard measuring cylinder for better accuracy with small charges of fast powder. Fill the dispenser at least 1/2 full or more. Rap the measure to settle the powder and make sure you operate the handle in the same manner each time. W231 meters very consistently in all my powder measures. Differences between throws is usually not measurable.
buck460XVR
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My Uniflow does better than .2 even with Unique. Never used W231 myself, but I do know it meters well.
+1 on the throwing a few charges to let the powder settle and make sure you throw the lever with the same motion everytime. I like using the "double-knock" method, especially when using Unique.
+1 on the throwing a few charges to let the powder settle and make sure you throw the lever with the same motion everytime. I like using the "double-knock" method, especially when using Unique.
Landric
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I have three Uniflows and all three are pretty much dead on with every powder I have tried from Trail Boss to AA#5. Sometimes I get a .1 grain variation, but I'd say all three of them are dead on 95+% of the time. Its really quite impressive.
wyocarp
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lord, my point was that there are a lot of variables.
There are other factors than what I have seen mentioned so far. How stable is your setup? Does your bench woble, shake, flex, etc. A reloading bench should be as stable as marble with a rock foundation. Hopefully your uniflow doesn't wobble or have any movement whatsoever.
I use mostly 231 in my 9mm. My uniflow throws almost all ball powders dead on. I get some variation with flake powders, maybe as much as .2, with big charges of extruded I may get .4
Be sure your stroke is consistent. I've seen a number of techniques all with good results. My personal method is a moderate speed reaching top and bottom with an audible tap at top and bottom dwelling at each end for maybe a bit over a half second for small pistol charges, significantly longer with bigger rifle size charges. By far the biggest factor is consistency. Also be sure the v notches are clean in your scale and check the knife edges on the shaft that goes through the balance beam for burrs with a magnifier. If you see anything you can give it a light touch with an extra fine stone (600 grit or so) at the angle its already cut, just don't get carried away you can mess up the geometry.
Be sure your stroke is consistent. I've seen a number of techniques all with good results. My personal method is a moderate speed reaching top and bottom with an audible tap at top and bottom dwelling at each end for maybe a bit over a half second for small pistol charges, significantly longer with bigger rifle size charges. By far the biggest factor is consistency. Also be sure the v notches are clean in your scale and check the knife edges on the shaft that goes through the balance beam for burrs with a magnifier. If you see anything you can give it a light touch with an extra fine stone (600 grit or so) at the angle its already cut, just don't get carried away you can mess up the geometry.
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