Uniflow metering screw

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wileybelch

New member
Like so many others before me, I have no confidence in the Uniflow large drum for pistol charges. So I wasted some good money buying an RCBS metering screw (small), #98843, thinking I could improve/upgrade my Uniflow performance for pistol charges. According to the sales lit at the RCBS website, it was supposed to fit any Uniflow. Guess what! It doesn't.
Does anyone know what/how this metering screw is supposed to fit? From the size of the powder chamber in the small metering screw, I'm not sure the small charges of Bullseye or 700X are going to be metered well, anyway.

BTW - there are a lot of postings stating that the normal, small drum is OK for charges up to .30-06. They imply that the belted magnums need the large drum. Consider a charge of 60 - 70gr IMR4350, or worse. Years ago, I started double throwing a 30 - 35gr charge to reach the needed magnum case charges. Since all careful reloaders visually check the powder before seating a bullet, I've never thrown a short charge. So, who needs the large drum? If you're really interested in the value of double charge throwing, do your own statistical study of the results of throwing two small charges of a stick powder vs one large charge. The double throw doesn't work on fully automatic progressive presses (obviously).

Love to hear your thoughts.
wileybelch
 
I have an old Uniflow that I changed over from small to large, or large to small...I do not remember which now. Nevertheless, I had to replace both the adjusting screw and the drum. The adjusting screws have a integral "disk" on the end that fit either the large or small metering chamber. I still have the spare drum and adjusting screw laying around someplace...after the change-over, I never had a need to use the originals.
 
I could have written dahermit's post, as my story is nearly exactly the same.

I bought my Uniflow when I first started handloading in '84. It was part of a kit, actually. Anyway, I switched to the small metering screw & drum assembly when I first got it. Having no previous loading experience, I just kind of logically knew that I'd be needing the small one. The large assembly is around my father's house somewhere.

The small assembly works great. I can meter Bullseye accurately down to 1.8gns - at least. The's the lowest charge I've ever attempted.
 
In the beginning both drums were included in the price of the powder measure, then it became either or. Problem, the cost of the additional drum with part cost more than the original cost of the Uniflow with both drums.

I also have the Little Dandy with rotors.

F. Guffey
 
As I understand the responses, the small metering screw only fits the 'small' drum and the large metering screw fits only the large drum? Is this true??? RCBS doesn't say anything about this requirement! I will closely scrutinze any RCBS products in the future for failures to communicate the performance of their product. Probably will find another vendor whose products are clearly promoted.

This project was part of setting up a Hornady Projector press with case activated powder drop attachment. This project is another messy story.

Thanks for the help everybody!
 
My uniflow (c. 1985) came with both drums. The small drum (IIRC) will drop full charges of W760 for 30-06, but if I switch to another powder (other than ball), for that cartridge, I need to go to the large drum. Another reason I like 760 in my 30-06...:)

I don't use the uniflow for pistol, all my pistol is loaded on a couple of Square Deal presses.
 
As I understand the responses, the small metering screw only fits the 'small' drum and the large metering screw fits only the large drum?
Click to expand...

Yes, this is true. Sorry, we only implied so in our responses, and didn't specifically state so.

The small and large screws have corresponding small and large drums to fit them. As sawdustdad stated (and I implied), it used to be that when you bought a Uniflow (me, in 1984), you got both drum/screw assemblies. I guess such is not the case now.
 
BY the way this is true of most powder measures. They sell both small and large rotors and screws. They infer that you can reload pistol with the large rotor but that is not a good idea.
 
OK, everybody, here's the skinny on this thread. The measuring screw I mistakenly purchased fits only the RCBS Quick Change Powder Measure! Not the Uniflow. When reviewing this Quick Change product, the cylinder looks exactly like the Uniflow but has a cross pin feature to allow 'Quick change'ing of metering screws (if you want to) when switching between powder charges. A neat idea, but at $120 per powder measure, I'll pass. Does anyone know if the Quick change cylinder will fit the Uniflow measure?
 
I was lucky and found a used rcbs powder dump at a gun show that had the small drum in it. Now I have two complete units with large and small drums.
You may try looking for a complete second unit.
 
I bought a used Uniflow measure on E-BAY with the small Drum for 25 bucks . It is in better shape when my old one and both work well .
 
I have a RCBS Uniflow powder measure. How can I tell by looking whether it is a large or small drum?
Click to expand...

From MidwayUSA:

For reference:
Large Micrometer Adjustment Screw (Item# 654-966) fits RCBS Uniflow Powder Measure with a measuring cylinder with a 11/16" diameter metering chamber. This is the Uniflow Powder Measure where the Metering screw is removed from the cylinder, up through the powder hopper.
Small Micrometer Adjustment Screw (Item# 322-221) fits RCBS Uniflow Powder Measure with a measuring cylinder with a 1/2" diameter metering chamber. This is the Uniflow Powder Measure where the Metering screw is removed out through the threaded area of the cylinder.
Click to expand...
 
Assuming you bought this $15 metering screw:
151306.jpg
Don't toss your new small Quick Change metering screw, just buy a $29 Quick Change cylinder and the other sized $10 metering screw for the new Quick change and you turn your older Uniflow into a new Quick Change Uniflow. (BTW, the new tool uses only ONE drum....fits both screws.)

http://www.midwayusa.com/product/981626/rcbs-quick-change-powder-measure-cylinder?cm_vc=ProductFinding
981626.jpg


http://www.midwayusa.com/product/1458151306/rcbs-quick-change-powder-measure-metering-screw-assembly?cm_vc=ProductFinding
491964_lista.jpg


And if you want to take advantage of the new tool's quick drain feature order this $9 part:

http://www.midwayusa.com/product/627805/rcbs-quick-change-powder-measure-powder-drain-attachment?cm_vc=ProductFinding
627805.jpg


The Quick Change is RCBS's main powder measure now. Comes with both of the New RCBS Pro Chucker progressives, the 5 station, and the 7 station press. Both come with bigger powder hoppers, the 7 station version's hopper is even bigger still.

So far you can't buy the new bigger hoppers from Midway separately. But you can order them direct from RCBS parts. Maybe that will change once the production on the new presses normalizes.

491524.jpg
918661.jpg
 
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