RCBS Uniflow Powder Measure

[mikemyers]

I bought a new RCBS Uniflow Powder Measure many months ago - the one I had from the 1980's was sort of beat up looking from storage, and a new assembly wasn't all that expensive. It came with two "drop tubes", for large or small calibers.

I got it set up, and used it last night and this morning. I tried to adjust it for 5.2 but the range seemed to vary from 5.0 to 5.5, with most throws between 5.1 and 5.3.

I called RCBS about a different matter, and we also got to talk about my powder measure. The RCBS technician said that these measures come with a "large" measuring cylinder and measuring screw, and I should buy the small size. I'm surprised, as my instructions say nothing about this. Fortunately, I had those parts in my older measure, so they're now installed in the new powder measure.

She also talked about two "micrometer" style tools:

• RCBS Uniflow Powder Measure Micrometer Adjustment Screw Large 685 Diameter and
• RCBS Uniflow Powder Measure Micrometer Adjustment Screw Small 500 Diameter

For those of you who've used both styles, is the "micrometer" device a good improvement over the stock version?



The box my powder measure came in doesn't say anything about large or small. Had this tech support person not brought it up, I'd never have known I wasn't using the better measuring system for small loads.

 

[Reloadron]

From our friends at RCBS:

The Micrometer Adjustment Screw is the secret to faster reloading. Add the it to the Uniflow™ Powder Measure, and reloaders can record precise settings for their powder charges. Determine the load number and dial it in—time after time. It’s easy to install, too, as it simply replaces the Uniflow’s standard metering screw.

This is useful for those who want to record and depend on settings. I have one and never use it as I don't record settings and rely on them the next time. I adjust the powder throw for my desired charge weight, tweaking and scale weighing till I have my desired charge weight. Then I may run a hundred or more cases, every 10th or so case I run the charge over my scale. I don't need a micrometer adjust to do that. Not that I would hesitate to spend $50 but even having one I don't use it for my loading methods.

Just My Take....
Ron

 

[mikemyers]

Thanks; that makes a lot of sense. Once either one is adjusted, presumably the setting won't change.

My other question was that I didn't (know I needed to) do enough research. The RCBS catalog says that the Uniflow Powder Measure can be bought with either the smaller or larger metering components. Different part numbers.


What kind of repeatability should I expect from this device? +/- 1, or more than that?

 

[cfullgraf]

Yes, the micrometer stem does not make the powder measure throw any more accurately. It does make returning to a setting faster if you record the setting.

Also, I can use it to dial in a new setting in one or two tries. I weigh where the measure is set and use interpolation and the settings to determine the new setting. Alot less trial and error to get to the new setting.

 

[higgite]

IIRC, I believe RCBS claims +/- 0.1 grain. I actually get better than that out of mine with the small cylinder and W231 powder.

Edit: I guess I should add that I use my Uniflow exclusively with a case activated feed mechanism on a progressive press.

 

[tightgroup tiger]

What kind of repeatability should I expect from this device? +/- 1, or more than that?

That depends on what kind of powder you are running through it. Fine ball powders, yes, +1/-1.

With Unique or any of the other pistol powders that meter like corn flakes, who knows. +2 or 3 /-2 or 3.

Stick rifle powders are hard to run through them also.

 

[Bart B.]

My 1970's Uniflow came with both cavities.

No spec is listed on RCBS's web site for charge weights. But I wouldn't put one out if I made them 'cause I'd have to list all powders made and the specs I got with each of them listing specific operating instructions that would rarely be duplicated. Powder measures are like firearms; they perform to different levels of precision and accuracy as operated by humans.

I've heard of all sorts of charge weight issues about all measures. But properly operated the RCBS Unflow will have a decent spread good enough for 1/2 MOA rifle accuracy at worst out to 300 yards if all else is up to it.

 

[Jesse Heywood]

No spec is listed on RCBS's web site for charge weights.

Part of the reason is because the readings can change when you reassemble the measure. There is not a way to hit the exact spot with the meter.

I made a chart and it gets me close. I have about 15 powders in my cabinet.
I also use the large rotor and mike for handguns. 700-X, 800-X, unique, the dots and the measure still throws =/- .1 gr. I must be doing something wrong!

 

[mikemyers]

With the larger components for measuring (didn't know there were smaller components for pistol loading until this afternoon), and using Unique powder, and running half a pound of Unique through the Uniflow first, to coat all the surfaces (as noted in the instructions), my repeatability was:

• rarely from 5.0 to 5.5 grains.
• usually it was from 5.1 to 5.3.

I tried to work the device the same way each time, but it took a while until I was consistant..... from then on, the range rarely exceeded 5.2 +/- 1 grain.

I spent two hours last night, and another two this morning, to load 50 rounds of 45ACP. I was checking lots of things, and this is the first time I've really done it since the 1990's. I guess I'm naturally very slow, but double checking everything made me even slower.


I'm debating with myself whether to buy a progressive press. After watching this video, it seems like once I get to learn what I'm doing much better, this might be in my future:

https://www.youtube.com/watch?v=gCOjenjFKmI​

I'd be looking into the latest RCBS progressive device, if my eyes didn't see a "pipe bomb" every time I look at it.


Something that would speed up what I'm doing quite a bit, is not checking the weight of every single round. I think every 10th round is what people here recommended.

 

[Ironicaintit]

I guess that would be nice, if you'd like to record that data in your logs.
But I wouldnt buy it. Once you get a feel for the stock adjustments, you can get right where you need to be, really quick.
Like the other guys have said, extruded powders are never going to throw all that consistent. With 4895 it throws really close...but not close enough that im not going to weigh 'em out anyways. (I like the top end, so I dont want to push my luck that far)
OTOH, With something like H110, you can pretty much set it and forget it. Its not even +\- .1 gr... mine drops the exact weight, every time.

Mine had a slight pebbly texture in the casting, and so I sanded it all down with 400 grit. Now its very smooth, and did seem to help consistency a little.
What really seems to help is a baffle!

 

[brutus51]

I find using the large large barrel and stem really helps consistancey in pistol calibers when using powders such as Unique, little less chop I guess.

 

[mikemyers]

Is this what you mean?

http://www.thehighroad.org/attachment.php?attachmentid=78980&d=1211856964

Just one of them, or two?

 

[cfullgraf]

Is this what you mean?

http://www.thehighroad.org/attachment.php?attachmentid=78980&d=1211856964

Just one of them, or two?

Yup that a tutorial on making baffles for various diameter reservoirs. Or you can buy the RCBS version which is made to fit the Uniflow reservoir.

I always have one baffle in my powder measures. I align the peak of the measure so that it is perpendicular to the rotational axis of the drum. In other words, the holes on the baffle should not be over the cavity in the metering drum.

I am experimenting with two baffles in one measure (Redding 10X). The jury is still out on the benefits here.

 

[mikemyers]

.....I always have one baffle in my powder measures. I align the peak of the measure so that it is perpendicular to the rotational axis of the drum. In other words, the holes on the baffle should not be over the cavity in the metering drum..........

Once again, something that sounds obvious, but wasn't before you wrote this. Thanks!!!

 

[Average Joe]

They should tell you on the box which cylinder it comes with, I went through the same thing, I didn't know there was such a thing as two cylinders, large or small. I found out later after it was too late....

 

[Mauser69]

General pointers

These issues apply equally to all brands and types of powder measures that measure weight by using a volume - I do not see them mentioned often enough:

First, ALL powders will settle some and compact from vibration. For some, like large flake powders, this can change the weight of a specific volume significantly. It will help a LOT with any powder to tap the base of the powder measure about 20 or 30 times with something like a screwdriver handle to get that settling done mostly before you start throwing charges. If you use a measure on a press where you go through a number of "cycles" between throwing a charge for each individual case (as opposed to throwing a charge sequentially for a lot of prepared cases all at one time), you will find that the vibration of the regular press activity will greatly help in making consistent throws.

For the same reason, using a baffle in a powder measure is important, as it will make the weight of the powder above the metering mechanism more uniform. This means the compaction level will not change as the level of powder decreases.

When using a mechanical powder measure, concentrate on throwing the handle the same way, with the same force while hitting the stops at the each end of the handle throw every time. Hitting the end of the throw with a little bump each time will aid in consistent throw weights.

 

[X-Ring]

One other thing you can leave the cylinder in the drop position so any vibration will have less effect. The handle can be mounted so it drops in the down position with the measure turned around so the metering stem is toward the back. Or you can leave the handle in the up position.

 

[Jesse Heywood]

I am now such a believer in the use of a baffle that I feel RCBS is doing the reloading a disservice by not one with every measure sold. The baffle makes that much of a difference.

 

[Bart B.]

My Uniflow came with an aluminum baffle.

I made one for an old Redding measure using an elipse calculator on the WWW. Used the resivoir inside diameter as the minor dimension to calculate the major one (minor X 1.414 = major) so when it's shape was cut out of cardboard then folded to a 90 deg angle, it would fit inside the resivoir peak up. Cut a small V notch at each end to let powder through.

http://www.endmemo.com/geometry/ellipsegrapher.php

 

[GW Staar]

Want to make your own baffle easily? Here's a PDF file you can print out and make your own. Use Aluminum sheet or just a pop can can be used. Actully if you print it on heavy card stock, I'd think that would work as well as aluminum. Print, cut it out, bend it and use it. btw if & when you print this make your your printer is set to "actual size" not "fit".

http://thefiringline.com/forums/attachment.php?attachmentid=91293&d=1376972489

RCBS has "graduated" to another system where the Mic part isn't used. They call it their Quick Change Model. They use the old measuring stem idea, but the stems quick release from the cylinder (no threads to screw in). The idea is to buy a stem for each load you use. Set it once and go. That's even faster (once adjusted the first time) than a mic. One really NICE feature on that one is that there is only ONE cylinder. It fits all stems/cavities, even a new 50bmg stem!

I have three Uniflows.....and since you can get upgrade parts for them from Midway and convert them to the Quick Change, I plan to convert one soon. You have to buy a single quick Change cylinder and the measuring stem or stems you want. Thing is.....if you have the wrong cylinder for your Uniflow and need the other size.....you could just convert! A Quick Change cylinder and stems as needed is all you need. Stem prices are cheap enough to buy multiples of, as needed, of either large or small cavity size.

 

[Jesse Heywood]

I have a QC conversion occupying drawer space. Believed the magical claims and tried it. Had issues with the fit of the release pin which made it a real pleasure to do the "quick" change. The only good part was the drain. The meters aren't cheap so if you use differing loads and powders the price goes high.

I went back to the mike and a chart. When I need to empty the measure I take it out of the turret and pour the powder out the top.

 

[cfullgraf]

RCBS has "graduated" to another system where the Mic part isn't used. They call it their Quick Change Model. They use the old measuring stem idea, but the stems quick release from the cylinder (no threads to screw in). The idea is to buy a stem for each load you use. Set it once and go. That's even faster (once adjusted the first time) than a mic. One really NICE feature on that one is that there is only ONE cylinder. It fits all stems/cavities, even a new 50bmg stem!

The Hornady L-N-L has replaceable metering inserts as well. Good idea and will work well for some folks.

They are not my cup of tea. I find I need to tweak the charge adjustment each time I load another cartridge and find the micrometer metering stems better for that. I can interpolate what the new setting needs to be and make fine, repeatable adjustments to get there.

I guess changes in humidity, water content of the powder, phases of the moon, how I hold my tongue and so forth call to me to make the minor adjustments.

The replaceable metering inserts are definitely worth a try, but I would not get too heavily invested in them until you decide you like the system.

But, the same can be said about trying the micrometer metering inserts.

 

[GW Staar]

I understand what you're saying, cfullgraf. We all experience the same powder variation where its usually necessary to tweak a little...that's a given. For me it doesn't make any difference whether it's turning the mic a little or the older mic-less stem a little. Yes, you can record the tweak with a new number using a mic, but it doesn't mean a whole lot when the next time you load you have to move it back. A quarter turn to the right may mean the same thing....and can be recorded if you want, also. I don't bother with that any more, not necessary.

What I mean is.....I use a scale to dial it in mic or not. Its just nice to have a set position really close to what your final tweak is. That was the beauty of the mic. Record it, look it up, and reset it......then tweak.

Now understand...I don't have the new system yet, but I have used the old stems for 40 years before the mics arrived on the scene.... What I THINK I'm going to like, is having separate preset stems in a drawer ready to snap in the cylinder, rather than getting out my data book and looking up the ball park mic setting to start with each and every time I change loads. Instead, snap it in, then tweak it a little...same thing only faster.

I can't verify what Jesse is saying yet.....except that if that happened to me I'd be calling the good folks at RCBS so they can send a fix, before I went back to the mics. They have a lot riding on this.....their new progressives come with them......they are going to give you the parts that make it work, I have no doubt.

If the only good part was the drain, I wouldn't buy one, since I use it on a progressive, with the case activated linkage, which means that I only have to unscrew the thumb screw and lift off the spring, and the whole hopper can be lifted and dumped in 20 seconds ... so the drain isn't needed. Screwed down to a base for use on a single station press....is another matter...it would be much more important and appreciated!

The metering screws are $10 for the large one and $15 for the small one. Worth it to me if it works, each one the price of lunch.

Heads up cfullgraf! I just noticed that Midway has some great clearance prices on the Mics right now! Either the prices are going up, or RCBS is phasing them out. Those may be your cup of tea!

 

[Jesse Heywood]

GW, I would say my issue was probably due to my big ham hands. I just couldn't get things to fit together and come apart as easily as I had hoped. My biggest gripe was the plunger's size. If it had a larger diameter shaft and cone with a larger head to pull on I would have had better results. It functioned as advertised, but could have been designed a lot better. The mike fits my operation better on my turret doing small runs for a dozen different calibers and 15+ powders. The mike is just easier for me.

 

[GW Staar]

Jesse, I just ordered a Quick Change Cylinder and a single Small Metering Stem along with some other stuff to make shipping more tolerable. The Quick Change parts cost $29 + $15. = $44 + shipping.

I will report on the Uniflow conversion in a new thread. If I don't care for it I will say so....I like my experience with most RCBS products....most. But when I dislike a product I'm not afraid to say so.......my hands are probably smaller than yours.....so.....we will see. I'd say $44 isn't a terrible loss if it doesn't work out.