Rcbs uniflow powder measure binding

N

nhyrum

New member
I recently got a uniflow powder measure, and almost every time I go to drop a charge, it binds, sometimes pretty good, other times I can barely feel it. Is this normal? Is it just "cutting"the powder to fit in the cylinder?

Also, is there an attachment that makes dropping into a scale pan easier? Unless I have the pan literally touching the the tube, it bounces and scatters everywhere.

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Cutting kernels is normal when using an IMR type stick powder.

Put the scale pan up against the drop tube, throw the charge, then lower the pan a little, the powder will pour in without bouncing out.
 
Also, is there an attachment that makes dropping into a scale pan easier? Unless I have the pan literally touching the the tube, it bounces and scatters everywhere.
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If you do not have the Uniflow powder measure tied down expect all of the problems listed. The Uniflow comes with small tubes/funnels that sit on the top of the case. You can hold the case and then operate the handle or you can place the cases in loading trays and then hold the powder measure with one hand and operate the handle with the other.

Spilling and bouncing powder: I would suggest you dump the powder into a case and then transfer the powder from the case to the scale pan.

F. Guffey
 
I've been using a RCBS Uniflow for years and agree with 44 AMP, long grain powders almost always cause it to "bind". I was taught when using it to always double tap on both ends of the stroke, the teacher saying is helped ensure consistency on each throw. After many years of putting up with throwing the charge, weighing the charge, almost always having to trickle powder into the pan to get the correct charge, I finally broke down and purchased a RCBS Chargemaster. Wow, what a difference it has made.

Follow 44 AMP's instructions on placing the pan against the powder drain tube and slowly lowering it, it solves the issue of powder going everywhere.
 
It's bolted to my bench.
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I knew that, now how high above the powder pan are you dropping the powder? With the Uniflow bolted down, place the case below the little green funnel and drop the powder into the case with no gap between the case and powder measure; and then, pour the powder from the case into the powder pan. It is possible to place the cases into a case holder/tray and then dump the powder into each case.

I have better luck with using the heel of my hand than my fingers, I have no problem with cutting grains of powder with my rotor; it is not like cutting wire and or nails. I also have adjustable dippers, one of them goes back 100 + years; I know, back then it could have been used for lead shot, it could have been used for powder and shot. Who knows? All I know is it is one very accurate little dipper, I will use it before I use a powder measure that runs a little ruff when cutting powder. I use the scale to adjust the powder measure, after I adjust the powder measure I start dumping and cutting and I check to see if something has worked loose.

And I have progressive presses, there is a leverage advantage when going to a progressive press; those little grains of powder hardly slow it down and are not as noticeable.

So adding a longer handle to the Uniflow could make cutting powder less noticeable.

F. Guffey
 
Rcbs uniflow powder measure binding
I recently got a uniflow powder measure, and almost every time I go to drop a charge, it binds, sometimes pretty good, other times I can barely feel it. Is this normal? Is it just "cutting"the powder to fit in the cylinder?

Also, is there an attachment that makes dropping into a scale pan easier? Unless I have the pan literally touching the the tube, it bounces and scatters everywhere.
Click to expand...

When measuring certain powders like "stick" or extruded powders it is normal to have what most refer to as a crunchy feeling as the drum cuts the powder sticks. Powders like for example IMR 4895 or H4895 are examples of stick or extruded powders making them a little more difficult to meter on the Uniflow and similar powder throws or measures.

When I wanted to weigh my charges I would use my uniflow to throw a slightly light charge just below what I wanted. I would do as FGUFFY suggested and throw my charges into a case and use the case to transfer my charge to the pan n my scale. Then I used a powder trickler to acheive my desired weight on my scale.

You should have case mouth adapters to make mating the case to uniflow an easy task. This will eliminate the powder bouncing in and out of the pan.

Powder%20Drop%20Tubes.png


For simple drops the pictured tubes are not required, the case mouth adapter fits directly to the base of the Uniflow powder measure.

Ron
 
F. Guffey said:
I knew that, now how high above the powder pan are you dropping the powder? With the Uniflow bolted down, place the case below the little green funnel and drop the powder into the case with no gap between the case and powder measure; and then, pour the powder from the case into the powder pan. It is possible to place the cases into a case holder/tray and then dump the powder into each case.

I have better luck with using the heel of my hand than my fingers, I have no problem with cutting grains of powder with my rotor; it is not like cutting wire and or nails. I also have adjustable dippers, one of them goes back 100 + years; I know, back then it could have been used for lead shot, it could have been used for powder and shot. Who knows? All I know is it is one very accurate little dipper, I will use it before I use a powder measure that runs a little ruff when cutting powder. I use the scale to adjust the powder measure, after I adjust the powder measure I start dumping and cutting and I check to see if something has worked loose.

And I have progressive presses, there is a leverage advantage when going to a progressive press; those little grains of powder hardly slow it down and are not as noticeable.

So adding a longer handle to the Uniflow could make cutting powder less noticeable.

F. Guffey
Click to expand...
I'll try dropping into a case, then dumping into the pan. Right now, I put my scale pan right up to the drop tube, where it touches. My drop tube has a small chip on one side about 5 o'clock, which let's the powder leave the tube, but not spill.

I am using stick powder, namely imr 4451 and h4350. But most of the time I'd compare it to cutting 12 gauge solid copper wire. It's pretty stiff. Could I have put the drum in backwards/upside down? It really only goes in one way that's logical to me. Handle on the right, lift to dispense, and drop to fill the metering cylinder again.

I do have two case mouth adapters. A "small" and a "large" that came with the measure. As of right now, I just hold the pan right to the mouth of the case mouth adapter, drop a light charge, put the pan on the scale, trickle the rest, transfer to the case, and while still holding the pan, throw another charge. That process doesn't bother me, other than the binding of the measure.

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It really only goes in one way that's logical to me. Handle on the right, lift to dispense, and drop to fill the metering cylinder again.
Click to expand...

I have more control when lowering the handle, and then I have case activated powder measures and lock outs meaning if there is no case there is no powder dumped. And then there is that 180° thing with the handle.

The Little Dandy is directional because of the retaining screw. The Little Dandy is my favorite powder measure.

F. Guffey
 
Cutting kernels is normal when using any powder thrower. A light thump helps. Except for when you're setting the thing up, you'd just drop the powder directly into the case. Otherwise, like 44 AMP says, just hold the pan right on the tube.
 
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