[biogenic]

Have a uniflow which is not consistent when dispensing the charges. It varies from charge to charge. I have it set for 8.5. It delivers 8.5 once or twice and then it delivers 8.8, 8.3, 8.7....
To be fair the only powder i've tried so far is Unique. Anything i can do to rectify the problem? I am using the big drum with a micrometer.

[NeuseRvrRat]

get the pistol drum with the smaller diameter cavity.

operate it in a very consistent manner.

[biogenic]

get the pistol drum with the smaller diameter cavity.

Thanks. Did some more research and you are so right... the big drum is accurate from 10gr and up according to RCBS.

[NeuseRvrRat]

i've used the small drum to meter tiny charges of W231 for .380 Auto. it did fine.

[R.W.Dale]

The large drum should dispense that much unique. Or at least mine would but I do have the micrometer stem.

I've found the biggest and best improvement one can make to a uniflow is to disregard the instructions and set the meter up to dump and therefore cut powder granules on the downstroke. Everyone whose tried it agrees that throw to throw uniformity is vastly improved simply because you have the weight of your arm following the motion through instead of just some wrist muscles going the wrong way

[HOWARD J]

I am not in a hurry anymore---I set unit to drop a couple tenths of grains below what I want & use a dribbler to come up to setting also I knock twice on the up stroke & twice on the drop stroke.

[brickeyee]

And put a baffle in the powder hopper.

[Swampman]

Wipe your measure, including the dispenser cavity, with a drier antistatic sheet.

Do as HOWARD1 suggested, tap twice on both the upstroke and downstroke, be as consistent as possible when doing so.

You could also try putting in a powder baffle. They're easy to make.

My Uniflow will usually stay within a tenth of a grain dispensing Unique using these methods.

[rajb123]

...small drums and the powder baffle work on getting consistency from small throws.... Are all the parts clean?

[BYJO4]

The small drum and meter should solve the problem. I use Unique all the time and my Uniflow will stay within plus/minus .1 of grain.

[brickeyee]

Are all the parts clean?

Coated with graphite is better.

They eventually get that way for the powder itself.

"Clean" is not actually desired.

You want it covered with the correct 'dirt' (powdered graphite).

[ranger335v]

No volume dispensing of dry granular goods is going to be highly precise at its best. The composition of the powder (flake, ball or tubular) contributes to the variation we can expect. Unique is a great mid-range powder but one of the worst to dispense. Inconsistant powder column and - most of all - inconsistant measure operation is the major factor in charge variations.

Weighing pistol charges is new guy stuff. Limit your average charges to maybe .3 gr below book max and just drop them into your primed cases like the rest of us, you will be safe and your ammo will work fine.

[A Pause for the Coz]

I am not a big fan of a baffle when trying to drop flake powders.
In my opinion, you need the weight of the powder in the hopper to pack out the air gaps.

But I have found you need to keep the measure at least 1/2 full.

I get less than a 20th of a grain variances with the two Uni's I have with Unique.

[cfullgraf]

I am also a big fan of baffles. Install the baffle so that the peak of the baffle is perpendicular to the rotational axis of the drum. This keeps the holes in the baffle from being directly over the metering cavity.

I also like the micrometer adjuster but they do not make the measure throw more precisely. They do make adjusting and returning to a setting easier.

Consistency of operation is the key. Do it the same way every time. I minimize vibrations as much as possible. Others like to wrap the measure at the stops of the metering cavity. Either way works fine but you must do it the same way every time.

After filling the hopper, throw 15, 20 or so charges to settle the powder column. Otherwise, it will settle while you are using it and your powder charges will increase in weight for a while.

I recently got a tip to wax the internals of the measure with Johnson Paste wax. While I have not seen consistency improve, powder is less likely to stick to the inside. I am still working with this.

I store a anti-static dryer sheet in my measures when not in use.

Hope this helps.