Uniflow 3 Picture Review

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GW Staar

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I guess I’m a collector of sorts ... of RCBS Uniflows.

At least I have, over the last forty five years, managed to acquire 6 of them starting with an early version that came with my Rock Chucker I press….that press and the Uniflow that came with it, were given to my Father-in-Law, when I upgraded to a Rock Chucker II press and Uniflow combo.

Since then, I bought a Pro 2000 Progressive press, which came with a Competition model Uniflow (the one with the Mic adjustment) ….. and I bought another Competition model so I could leave one set up with the large cavity cylinder and the other with the small cavity cylinder. So that’s 4 minus the one I gave away….so three really.

Then I bought a Pro Chucker 5 (and a Pro Chucker 7 Upgrade kit). Why on earth? Easy, that way I got 2 of the new Quick Change Uniflows for the price of one……and one has the big hopper that empties a whole pound of powder with one fill-up. So then I have 5.

Last month, being the curious soul that I am….especially about new RCBS tools…..I got a great deal on RCBS’s brand new Uniflow 3…….so now, I have 6. Eye rolls are appropriate….;)

Anyway……I decided I ought to share what this new Uniflow has to offer compared to all the others, especially since RCBS plans to equip their presses (even the big hoppered Pro Chucker 7 version) with this new incarnation….and for sure the coming kits starring their new single stage Rebel Press.

First picture below shows Uniflow cylinders over the years. Original Uniflow big and smalls at the top, including the competition model with it’s mic adjusting stem. In the front row of the picture is the still new Quick-Change models featuring one cylinder 2 sizes of stem inserts (left). And on the right, the brand new Uniflow 3 with one cylinder, one stem. RCBS obviously has decided that one size can do it all if it’s done right.
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Notice the stem on the new one is black……can’t see it…..and it’s actually worth seeing!;) So the next picture is a closeup:
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Notice it’s not flat! It is shaped to the diameter of the cylinder. So there's a flat on the shaft to keep it from rotating.
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Here’s a picture of both the Quick Change and the UF3 parts. On the UF3, gone is the spring loaded Quick Change bolt, replaced by the simpler brass one and the scaled stem screw with a flat that the brass screw tightens to. Notice the shaped end vs. the flat disk of the Q.C.

Above the stems are the keepers that the screws screw into and that the disk screws screw into. The new brass one is larger in diameter. Loosening either the brass UF3 bolt or the Q.C. bolt allows you to pull the whole stem out and replace it with a powder drain tube to fill your powder can back with what you don’t load. The drain tubes are similar but not interchangeable due to the little hole in the Q.C. model for the spring-loaded pin to drop in. (I will probably miss that pin in the UF3…..because it is easier to get both the drain tube and the powder stems to pop into place quickly. Way less fiddling) Well….the brass bolt is prettier at least.

The video below will show you what I mean…..while I liked the spring loaded pin, I have to admit, the fine tuning is easy and nice with the big adjustment screw....and the shaped stem head means that zero ... really is. The spring WAS a little stiff....the idea was to be able to loosen the screw just a little.....pull the pin outward and pull the stem out. Turns out the spring was a little stiff for that...especially if the Uniflow wasn't mounted to a bench or press. But I sure liked the instant "snap" in place stem locating that it offered.

Below is a closeup of the new UF3 screw’s scaling….similar to the pre-Competition Model stems, pictured with it. My old eyes can see the better contrasted scale much clearer….no magnifier necessary. Thank you for that. I had to move the light and camera just so so that the old Uniflow scale would show up in the camera. (the lower one)

Notice that the big nut on the UF#’s metering screw, has marks to help with repeating adjustments……black on black! I had to fix that with a white permanent paint stick (Meanstreak brand is what I use, wipe in on, mineral spirits on a rag wipes off any excess)
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The nut turns nicely for fine adjustments of powder charge even once the brass cylinder screw is against, but not too tight against, the stem. (keeps it from turning....remember it's shaped end needs to fit the cylinder) So one turns the big nut to adjust it just so, then you tighten the brass screw tight. I do like that a lot! Give and take! Miss the QC pin, but this is probably worth it!
“Meanstreaked” adjustment screw to save my eyes. Video below:


Now for the best part, the hopper…….finally……it screws into the Uniflow casting!.......and you will be able to buy the big hoppers separately! RCBS says the green plastic is anti-static as well……well….with egg on my face…I have to tell you that I tested that….poorly. I forgot to clean the new Uniflow3 before I poured Unique in it……and yes it was coated with shipping oil to prevent rusting……and the instructions do indeed warn to clean with solvent before pouring in powder……I knew that…..brain fart pure and simple.

Below is the old press-on hopper……notice the rough cast iron that the powder has to roll over.
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Compare with the new…..screw threads are smooth on the inside….straight down….. should meter better.
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Below: Notice more machined surfaces on the Uniflow 3. Notice the threaded bolt hole in the side of the casting……just a guess, but I’d say the Pro Chucker’s will get a new rifle bullet collator tied to the case activated linkage….I hope.

Also notice there are more threads to screw into the case activated linkage (for progressive presses) than the old Uniflows. That will make them easier to adjust to more calibers. Things are looking up.

The easiest way to spot a Uniflow 3 at a distance is the wider flange at the top (necessary because of the threads inside the mouth for the screw on hoppers………and the reinforcements in the casting below said flange.
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A last shot of the difference between the Quick Change and the Uniflow 3…..
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Any negatives? Just one so far. The brass screw holds a setting just fine on the metering screw……..but that’s gone just as soon as you loosen it……..say to insert the powder dump screw?

I have this simple mod…..rolling eyes…. (what were they thinking) Okay it’s a simple fix….nyon washer and thin metric nut from Ace Hardware....Just a nylon nut that size would be better and simpler....

The last thing I will miss when the Quick Change disappears is the ability to buy additional stems and preset them for your common loads……that was really a unique feature…..very convenient ….the quick part of Quick Change.

Maybe RCBS will, post-covid, start selling the new stem assembly separately (with a nylon nut) for that purpose ..... hope so.

Oh! You all might be interested in the powder cavity hole sizes over the years:

Old Large: .685"
Old Small .500"

Quick Change Large: .624"
Quick Change Small: .498"

New Uniflow 3: .624"
 
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I don't have one, know nothing about them, but you did a wonderful job of explaining the care and feeding of those measures.
 
How would you rate the accuracy of this new powder measure between pistol and rifle loads? I know it is very dependent on the type of powder but I'm just curious because I'm looking to pick one of these up to replace my Lee PPM. Thanks.
 
Too early yet for me to make a judgement for the powders I use. I'm yet to put it in service. But I will soon. Today I have a new 3D printer, that just came in, to put together....so first things first!;)

Other Uniflows are accurate enough in my experience, but they excel with learning some "technique". Everybody has their own that they like for single station presses, but on progressives there's no way to "double strike at the end of the fill stroke like I used to do using single stations....but it was accurate enough....best with ball powders, then small stick powders, less so with long stick powders, and flakes.....well you know flakes. Yet with flakes like Unique it had to be a very big variance to even see it on the target.....and I never did.

RCBS says this is the most accurate of their Uniflows......"Machined reference surfaces for exacting tight tolerances allowing for a dispensing range of- 0.5-95 grains- 0.1 grain to 0.3 grain accuracy". We will see, soon.

The diameter of the powder cavity is smaller than that of their old large cylinder, and that's good. The old ones were so big that it was hard to be accurate with small loads......so they made the small cavity cylinders. Now with the intermediate sized cavity, small loads will likely be more accurate, and large loads are still possible. At least that is what is being preached. We will soon see.

In the manual (which they recently added to their web page on the new powder measure), they use two Alliant powders to indicate the metering range of the measure:

Reloder 22 extruded powder can meter 97 grains - 3 grains.
300MP ball powder can meter 100.0 grains - 0.5 grains.
 
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I did some editing last night, to clarify a few points....
For any who might have copied and printed this thread for reference (maybe for a future P.M. buy)......you might copy it again, and toss the old one.
 
I noticed this morning that Midway USA finally has the new Rebel Press/Uniflow3 Kit in stock. $400. Just the Rebel Press? Not yet.
RCBS Rebel Master Single Stage Press Kit
https://www.midwayusa.com/product/1022387772?pid=270065

Buy Green get Green is back.......that means you buy that kit you can get a $100 rebate!
 
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Do you know if the RCBS powder baffle will fit into the new uniflow? I broke down and decided to order a uniflow 3 because of the rebate going on at the moment.
 
Do you know if the RCBS powder baffle will fit into the new uniflow? I broke down and decided to order a uniflow 3 because of the rebate going on at the moment.
Where did you order? The places I looked we out of stock or pre order only? Figure for 50 bucks I will update the Pro2000 Competition PM.
 
Do you know if the RCBS powder baffle will fit into the new uniflow? I broke down and decided to order a uniflow 3 because of the rebate going on at the moment.

All my Uniflow hoppers measure the same I.S. diameter, except for the big 1# hopper.....even the 40 year old one.
 
The diameter of the powder cavity is smaller than that of their old large cylinder, and that's good.

How about the UF3 vs QC cavity? Will the UF3 metering stem fit the QC drum? I can make a different locking screw if that's a problem.
 
Do you know if the RCBS powder baffle will fit into the new uniflow? I broke down and decided to order a uniflow 3 because of the rebate going on at the moment.

Google "Uncle Nick's Powder Baffles Template" and download. All you need is an opened up soda can and scissors or I used a piece of alum flashing left over from a job, to make a baffle for my Lyman 55. Instrucrions are fpr ANY size baffle.
 
How about the UF3 vs QC cavity? Will the UF3 metering stem fit the QC drum? I can make a different locking screw if that's a problem.

Yes it's the same. The locking screw will not fit. The Q.C. screw is a lot smaller.

Look at the new brass screw below: A 1/8-27NPT die screws on......the shaft at the end is .269" in diameter.
The Q.C. screw has a .185 Dia. spring loaded pin.....it's threads are smaller too....5/16-NF. It appears, looking at the cylinders below, that RCBS just increased the size of the threaded hole.....not changing the center location. A machinist could without a doubt change Quick Change cylinders to U.F. 3 cylinders just by drilling and tapping using the same center.

index.php

The Quick Change lock screw locks into the hole in the screw shaft nut shown above to the right of the Q.C. cylinder. Never touches the shaft itself.

Totally different, the U.F. 3 lock screw tightens against the flat of the shaft itself. The shaft nut is two pieces making it able to screw the shaft in and out if you just slightly loosen the brass lock screw......the shaft itself doesn't even turn....a good thing since it's shaped to fit the cylinder's curve only one way.

Nice write up.

Would you be willing to do 10 drop weight measurement with different powders?

Can if you're patient.....this week I'm trying to focus on learning my new toy.....a Creality CR10 v2. Blame AR-Bossman, Ed Dwan, and jmorris.
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Your in trouble now (time wise), with a new toy like that your only limited to your imagination. Looking forward on how this works out. I've been looking at them but never pulled the trigger.
 
The natural reaction is fear........yes.......flat skeered.....mostly about whether this old dog and learn anything new.....;) So many videos.....and after a while.....ZZZZZZZZ.
 
GWS, thanks for the info. I have a QC Uniflow. If/when they make individual UPM3 metering bars available, I’ll probably pick one up and see if I can make a lockdown screw that will work with my QC cylinder. I’m perfectly happy with my QC measure, but a man’s gotta do what a man’s gotta do. ;)
 
Higgite: What I found with my Quick Changes were that I didn't use the spring loaded feature for anything other than for snapping a stem in......for that it's super.....snap....you know its set in the right place. As for using the spring to pull for a quick release, I found the spring too hard to pull.....you have to be in just the right spot, with some bod leverage available. So I found it quicker to just unscrew it until the stem can be pulled out.

They must have figured the same thing, because with the U.F.3 that's the only way......unscrew the lock screw. I tried more than once to unscrew it just a little, but realized that you can't pull the stem out unless the screw is out. Unscrew it a little to adjust the powder cavity, remove the screw to change it for the powder dump tube.

I'm looking for metric nylon nuts to screw on the stem's end.....to prevent losing a setting, when I want to dump powder.....that would be ideal. Look for RCBS to add those soon.
 
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Great review and information.

Personal quirk, but I prefer to replace the wave washer with a fat o-ring. The settings don't seem to come undone as easily with an o-ring.
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Interesting idea too.......may look into that. That would mean I can just use the chrome nut I found at Ace and not worry about marring the U.F. 3.
 
I know this is from several months ago but glad I found it. have one of these on the way from grafs. Will probably either make a nylon nut or use the nut and o-ring to keep from losing settings. Mainly got this to do small pistol charges. Got a competition pistol measure a while back and it had a broken hopper when I got it. Hoping this one works out. Great write up.
 
GW Starr,
liked the presentation...awesome. one question. thinking of buying the uni-3. will the older stands that i used for the original
uni-flo`s work with the new unit or would you have to purchase the "new advanced powder measure stand"?
 
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