Uniflow Question

[hdwhit]

I have an RCBS Uniflow Powder measure that I bought second-hand in 1978 or 1979. The Uniflow was still new in the box. I know this since the seller bought it along with equipment when he wanted to get into reloading and stored it in my father's storm cellar. He unexpectedly became a father and sold me all of his reloading equipment (under the circumstances, I paid him near retail price).

I have used this Uniflow now for 40+ years. Most of this time has been metering IMR powders.

I learned to spot-check the powder throws because one in every 200 or 300 would turn up "light". The next throw would turn up "heavy" by almost exactly the amount the prior throw was "light". I usually throw charges slightly "light" and then trickle them up to the desired weight so this was a minor inconvenience.

But, in the last year or so, the "light" then "heavy" throws are now happening about every 25 rounds.

Has anyone experienced this?

Do you know what's causing it?

Can it be fixed or do I need to contact RCBS for assistance?

Thanks.

 

[Blue68f100]

Common problem with extruded powders. It's should be well seasoned by now. You could clean it, but then it would need to seasoned again. I moved up to auto dispenser.

 

[BBarn]

The light followed by heavy throw you describe is typically caused by a small bridge of powder formed in the drop tube, which is then cleared by the latter drop. I find it common with several of the slower stick powders.

Happens to me mostly when using the small (22 cal) drop tube. Not sure why it would be worse now unless the powder is cut a bit tougher or is a little more sticky. Might remove the drop tube and check for roughness or debris.

 

[Toprudder]

Don’t know what method you use to operate the measure, but I always tap the charge handle a couple of times against the stops, not only to help settle the powder consistently in the measure chamber, but also to make sure all the powder makes it out.

 

[BWS]

Most of my cast rifles love stick(logs) powders. Even though,more often than not,they're done dropped/trickled.

But one thing this teaches you after awhile is technique. On a uniflow,like Toprudder posted,the tap at the top is what makes them consistent. I usually just use one,then on the handle's downstroke or dump stroke,the first few mm's of the stroke will tell whether the kernels settled on that previous upstroke.

I can predict with uncanny accuracy if the downstroke is going to be cutting kernals in that first bit of handle movement. Cutting kernals isn't bridging but it isn't far from it. Just sayin,because I'm certifying each throw,it's easy to figure out what a "bad" throw feels like.

So,on a few rifle loads that don't require a trickler,the bad or funky throws get dumped back,and just run them again. May not be the perfect solution or answer but,works here for me. Good luck with your project.

 

[Ironicaintit]

Maybe your throwing the lever with less force than you used to?

I use the large drop tube for anything 30 cal and up. 223 is pretty much the only one I use the small insert for.
Also, I swing it pretty briskly, hitting it against its stops firmly. I get good, consistent drops that way... or at least as consistent as the particular powder will allow.
The double tap method works too; I just couldn’t get used to it.

 

[hdwhit]

Thank you for your thoughts. Sorry for the delay in responding. I had to have surgery for cancer and it took a while before I felt like replying.

In my prior post, I failed to reference technique in using the meter, but as my prior posts on THR will demonstrate, I have long used (and long recommended) strongly tapping the Uniflow when it was at the top of its stroke; a technique I continue to this day.

Also, the problem has continued regardless of whether I am using IMR-4198 which has long grains, IMR-3031 with shorter grains, or IMR-4064 which has shorter grains still.

I just want to know if others have experienced the same thing? If so, how did they resolve it? Did it turn out to be a wear issue with the measure itself? Or was it only a question of technique?

 

[Toprudder]

Good luck with your recovery!

 

[cfullgraf]

Don’t know what method you use to operate the measure, but I always tap the charge handle a couple of times against the stops, not only to help settle the powder consistently in the measure chamber, but also to make sure all the powder makes it out.

I've found Toprudder's method helps with my Uniflow. I also have a baffle in my Uniflow.

Finally, I try to stay with the metering drum at about 1/2 range or so. If the charge gets small with the rifle drum, I'll use the pistol drum.

I have found operating at the extremes of the settings for powder adjustments can cause higher variability of the powder charge dispensed.

Finally, I use Redding 10-X for pistol charges, an RCBS Uniflow with the small drum for small rifle charges (223 Rem, 204 Ruger, etc), a Midway Indispensable Powder measure with the rifle drum for rifle cartridges in the 30-06 class of powder charge.

 

[Mr. Zorg]

Good luck with your recovery!

+1 from me to the OP as well. My wife & I have both had surgeries for cancer, plus one of our dogs. I'm now just past 4 years since with no signs of recurrence, one of our dogs is at 7 (calendar, not dog) years with no sign of recurrence, and my wife's at 13 years with no signs of recurrence. I wish the same for your future.

I can't help with your powder thrower question but wanted to put that out there.

 

[ballman6711]

Might remove the drop tube and check for roughness or debris.

I would also do this.

Wishing you a full and speedy recovery. I'm currently going through a medical issue with my gf, she had a ruptured brain aneurysm at the start of Sept. She may be coming home next week, but these medical issues can sometimes be a long recovery.

chris

 

[rfwobbly]

Don’t know what method you use to operate the measure, but I always tap the charge handle a couple of times against the stops, not only to help settle the powder consistently in the measure chamber, but also to make sure all the powder makes it out.

• Technique is your number one problem. Toprudder hit the nail on the head. I call this technique "Knock-Knock" because it involves tapping the handle against the stop twice at the top and bottom of the 'throw'. Raise knock-knock; lower knock-knock.

• A powder baffle will add some consistency to your powder drops too. Buy one of these: https://www.midwayusa.com/product/1012934592?pid=493217

• The Uniflow also has 2 rotors available. Always use the powder measure cylinder with the smallest bore size that will get the job done. https://www.midwayusa.com/product/1012954590?pid=917289

Hope this helps.

 

[hdwhit]

Don’t know what method you use to operate the measure, but I always tap the charge handle a couple of times against the stops, not only to help settle the powder consistently in the measure chamber, but also to make sure all the powder makes it out.

I always give the powder measure body a sharp tap with the pinky side of my hand. For nearly 40 years, this was sufficient to ensure uniformity.

 

[hdwhit]

Maybe your throwing the lever with less force than you used to?

I use the large drop tube for anything 30 cal and up. 223 is pretty much the only one I use the small insert for.
Also, I swing it pretty briskly, hitting it against its stops firmly. I get good, consistent drops that way... or at least as consistent as the particular powder will allow.
The double tap method works too; I just couldn’t get used to it.

Entirely possible that at 60, I'm not as robust as I was in my 40's.

Also in the back of my mind is that the plastic in the hopper is 40+ years old and may not stand up to being swatted like it did in the 1990's.

 

[hdwhit]

Good luck with your recovery!

Thank you.

As I understand the doctors, a follicular thyroid cancer that is still within the "capsule" doesn't require anything other than surgical removal and periodic monitoring by the primary case provider.

So, once my neck relaxes enough that I can go around without looking like I'm trying to sure my shoelaces are tied, I should be fine.

Thank you, all, for your concern.

 

[JJFitch]

Good luck with recovery, your good attitude will help in many ways.
I'll dealing with degenerative bone disease in my neck .It's changed my life in ways I couldn't have imagined. Life goes on...

Static electricity might be causing the bridging. The air can be drier at different times of the year. Along with taps and baffles, ground your tool to the center screw of a nearby A/C outlet. This will help mitigate the static bridging.

* I had a bunch of erroneous powder drops. After trying all the above I found a small piece of Styrofoam in the drop tube! The powder passing by caused bridging! Looked like it came from the seal inside the powder container cap!

Smiles,

 

[hdwhit]

I've found Toprudder's method helps with my Uniflow. I also have a baffle in my Uniflow.

Finally, I try to stay with the metering drum at about 1/2 range or so. If the charge gets small with the rifle drum, I'll use the pistol drum.

I have found operating at the extremes of the settings for powder adjustments can cause higher variability of the powder charge dispensed.

Finally, I use Redding 10-X for pistol charges, an RCBS Uniflow with the small drum for small rifle charges (223 Rem, 204 Ruger, etc), a Midway Indispensable Powder measure with the rifle drum for rifle cartridges in the 30-06 class of powder charge.

I think my prior posts addressed your first two paragraphs.

I THINK this is the small drum since I've never used it to dispense more than 25 grains of Winchester power for use in 223 Remington, but I will check.

As soon as I can find what moving box the Uniflow was in when we moved from Texas to Arkansas.

 

[George P]

Add a powder baffle to the Uniflow, that will help

 

[cfullgraf]

I think my prior posts addressed your first two paragraphs.

I THINK this is the small drum since I've never used it to dispense more than 25 grains of Winchester power for use in 223 Remington, but I will check.

As soon as I can find what moving box the Uniflow was in when we moved from Texas to Arkansas.

Thanks for your comments but I do not have I problem operating my Uniflow powder measures. I have two, one used on a single stage press and the the set up for progressives.

I was just stating what I've found that works for me for consistent powder drops.

 

[mkl]

Post #12 pretty much nailed it. I call it the "double tap" method and have used it for over 40 years on my Uniflow. All of his other points are valid and almost exactly reflect the way I load and have never had a bridging problem. Only other thing I can think of is there any step in your powder handling/transfer method that could cause a static electricity build up after several rounds so the powder would try to cling to your drop tube. Try grounding the Uniflow and see if it helps.

 

[George P]

Post #12 pretty much nailed it. I call it the "double tap" method and have used it for over 40 years on my Uniflow. All of his other points are valid and almost exactly reflect the way I load and have never had a bridging problem. Only other thing I can think of is there any step in your powder handling/transfer method that could cause a static electricity build up after several rounds so the powder would try to cling to your drop tube.

Wipe the inside down with a dryer sheet now and again and problem solved regarding static