Weird issue with either Square Deal B or RCBS electronic scale

[Shuz]

I'm trying to load some 9.5g of Unique in my Square Deal B set up for .44 mag. Small charge bar is in. After getting the measure to throw real close to 9.5 as weighed on my RCBS electronic scale, I decided to throw a couple of check charges to make sure I'm close to 9.5. Next throw was 10.1 and then 9.7.So I decided to run 10 cases threw just the powder die and see what the weighed. The next ten cases ranged from 9.1 to 10.2, and that is just not acceptable.
I called Dillon and they said to wipe the inside of the powder measure and all components with a dryer sheet, so I did.
Next 5 throws went from 9.6 to 10.3, still not acceptable to me. So I decided to try some 2400, because we all know that Unique, as a flake powder, doesn't measure all that well. The 2400 on 6 throws went from 16.6 to 17.3. Again this is not acceptable.

I checked my scale with the check weights and all seems normal with the 200 and 500 gram weights. Perhaps on light charges the scale has gone south?

Dillon gave me an RMA to return the powder measure for their inspection, but before I did that I thought I'd call RCBS today and talk to them about their electronic scale. This scale is over 30 years old and has given me trouble free service thus far.

Any suggestions would be appreciated.--Shuz

[DonHowe]

I remember once throwing charges of Unique from a RCBS Uniflow then weighing each charge. Over 20 or more charges I got about the same inconsistency you experienced. I switched powders in what I was loading at the time.

[joe leadslinger]

Did you check your charges with a beam scale ? If not I would try that first. Electronic scales can and do go south on you.

[swheeler]

I have found the same with Unique, not so bad with 2400. Titegroup meters well as does most ball powder H110-W296, Accurate #9

[country gent]

While it may be the scales I would check the powder measure out first. A quick check on the scales would be to weigh a test weight 10 times and see if it varies. With your charge range a 10 grn weight would be a good starting point.

As to the powder measure I would disassemble it and clean it very good with acetone or alcohol. Inspect it check all springs and parts during reassembly. A little stickiness can cause variations in thrown weights. Check the nylon bushings closely for wear and or distortion. The measure needs to work smoothly and easily.

[Larry Gibson]

Shuz

Nothing wrong with either the RCBS scale or the SDB. The small powder ball just has too much powder surface are with that charge to throw consistently with a flake powder such as Unique. UNIQUE WILL JUST NOT "SCRAPE" OFF CLEANLY. Use the large powder bar. That's what I use with my SDB to load my 7.5 gr 44 SPL loads and my 8.5 gr Unique 44 magnum and 45 Colt loads. The large powder bar has a much smaller "scrape" off area and thus throws a much more consistent charge.

[mdi]

I have found very few powders that would weigh consistently +/-.1 grain with the three different measures I own (Unique wasn't one). When I was "dialed in" with my Lee PPM, I could hold .1 grain variation of W231 (I used a lot of that powder). Another consistent powder is a fine ball powder, WC820. There's bunches of "tricks" to get more consistent powder charges from "personal vibrators" aquarium pumps, knockers on the measure, and "raise handle, tap, tap, tap, lower handle" methods. Press wobbling, shell plate wobbling, inconsistent operation all play a part, but I gave up, about 30 years ago, trying to get consistent charges of +/-.05 grains of any powder from any mechanical powder measure. When I'm working up a load I'll "throw short and trickle up", or my "jes banging" ammo I'll live with a .2-.3 grain variation...

[Shuz]

Shuz

Nothing wrong with either the RCBS scale or the SDB. The small powder ball just has too much powder surface are with that charge to throw consistently with a flake powder such as Unique. UNIQUE WILL JUST NOT "SCRAPE" OFF CLEANLY. Use the large powder bar. That's what I use with my SDB to load my 7.5 gr 44 SPL loads and my 8.5 gr Unique 44 magnum and 45 Colt loads. The large powder bar has a much smaller "scrape" off area and thus throws a much more consistent charge.

Larry
I started out with the large bar and got erratic readings so I went to the small bar!
What is the typical variance you get with your Square Deal B and Unique?

[swheeler]

Shuz: I think if you are ever going to be satisfied you will have to change powder to one of the ball type. I was loading on a SDB 45 ACP, mostly Red Dot but Unique too, switched to W231 because of charge variations like you experienced. "Close enough" or "it always goes pop"just wasn't good enough for me, as I suspect it is not for you either;-) I know you probably don't want to buy another powder, but when the Unique is gone it is something to consider. Scot

[swheeler]

....and the SDB got away but the Lee Pro 1k gives me .1 gr charge variation with the W231. When the last of the 231 8 pounder is gone it will be replaced with AA#2 most likely, cleaner.

[Shuz]

Looks like the problem is solved. My old RCBS Powder Pro needed calibration! At least after I calibrated it the charges that were thrown read within .1g of the RCBS balance beam scale that I still cling onto. Thanks for all the suggestions!

[Larry Gibson]

Larry
I started out with the large bar and got erratic readings so I went to the small bar!
What is the typical variance you get with your Square Deal B and Unique?

Glad you've solved the problem. Just finished weighing 10 charges of Unique in SDB with large charge bar. I just set the weight close enough to 8.5 for this test. Basically the average was 8.6 gr with +/- .1 gr. Each charge weighed on Ohaus 10-0-05 scale. Beam pointer never rested below 8.5 nor above 8.7 gr.

8.5
8.7
8.6
8.5
8.5
8.6
8.6
8.6
8.7
8.6

[swheeler]

Shuz glad you got it. Someday you will use up that flaming dirt and get with the program!:kidding: