TESTED: RCBS Uniflow III Bench Powder Measure

The RCBS Uniflow III is the latest bench powder measure from RCBS, and in this article, we’ll take a hands-on look at this new powder measure, and put it to the test!

About the RCBS Uniflow III

Here’s the information from the RCBS Uniflow III product page:

The Uniflow-III Powder Measure is the most accurate Uniflow that RCBS has ever produced. The UPM-III throws consistently accurate charges reload after reload. The exacting tight tolerance allow powder to pour uniformly from the measuring cylinder and into a case, thereby eliminating the hazards of overloads caused by clogging when charges are dumped. The UPM-III changes easily from charge to charge of the same powder type without having to empty the powder hopper. The NG resistant anti-static threaded hopper is large enough to hold half a pound of extruded powder or one-third pound of flake powder. New on the UPM-III is the ability to use one metering cylinder and rotor for both rifle and pistol to throw charges from 0.5 grains to 95 grains. The new threaded hopper makes disassembly for cleaning quick and easy.

Note: The UPM-III Powder Measure should be used in conjunction with an accurate powder scale for setting the original charge and for checking charges occasionally during the run. Not for use with Black Powder line.

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- NG Resistant, anti-static hopper- RCBS limited lifetime warranty

Key Changes for the Uniflow III

*Note: when installing the metering insert, ensure that the flat side of the indicator rod (with engraving) is pointed towards the brass screw as shown in the picture above. Tightening the brass screw should lock in your setting.

Compared with previous models, the Uniflow III makes the following improvements:

  1. New Metering cylinder and Screw Design- Allows us to have one unit that works for both rifle and pistol.  Before had to buy either Rifle or Pistol unit, and purchase a new assembly if you wanted to load the other. 
  2. Screw in Hopper – Prior to this the Uniflow powder measures had push in fit hoppers.  This is easier to get all the kernels out of the unit when switching powers as you can unscrew the hopper and have access to the body to wipe kernels out.
  3. Machined Reference Surfaces – The center slot is machined for tighter lockup
  4. Laser engraved reference marks for easier viewing and adjusting
  5. Ships with quick drain attachment

What’s In the Box

The RCBS Uniflow III comes with the following as pictured above:

  • Powder measure assembly
  • Handle and mounting screws
  • Drop funnels: 30 cal and 22 cal
  • Cap
  • Quick drain insert
  • Metering insert (universal)
  • Lock ring
  • Press mount bracket
  • Instruction booklet

Consistency Testing

I decided to test the RCBS Uniflow III with three different powders. Ten throws were weighed for each powder after a careful prepping of the powder measure, and run-up for each powder. And here are the results of consistency testing with each! Note: all units are grains (weight).

Hodgdon H-4350

Accurate Magpro

Hodgdon H-1000

I was very surprised at how well Magpro metered in this powder measure: this is the most consistent result I’ve ever measured with a powder measure. Overall the results were very good, but Magpro really knocked things out of the park!


The RCBS Uniflow III powder measure is a great device for metering precision powder charges. I’ve used this powder measure for a year now (as seen in the UR Micro Cabin reloading setup, see picture above), and it has been working very well for me. The new features alone warrant an upgrade! The advanced stand from RCBS is a great accessory as well.

Get Yours

The RCBS Uniflow III powder measure is in stock at Midsouth Shooters Supply (as of the writing of this article). It’s got a great rating at Midsouth, a great place to pick one up!

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One thought on “TESTED: RCBS Uniflow III Bench Powder Measure”

  1. Interesting. It would be nice to know the characteristics of each powder – stick, ball, flake. I’m not familiar with those powders. My old Uniflow is poor with stick, excellent with ball or flake.

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