Ultrasonic Cleaner Cause MV Increase

Bloody_Tailgate

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Is it common knowledge that cleaning brass with an ultrasonic cleaner will increase muzzle velocity? I'd never used one in the past as I always tumbled in walnut media (for 20+ years). A friend recently let me borrow an ultrasonic cleaner and I noticed some weird velocity changes. Essentially, when I clean using the ultrasonic cleaner I am averaging 35fps increase over walnut cleaning.

I attribute this to the lack of carbon in the neck acting as a lubricant. Is this in line with what others have seen?
 

JLP.Payette

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Is it common knowledge that cleaning brass with an ultrasonic cleaner will increase muzzle velocity? I'd never used one in the past as I always tumbled in walnut media (for 20+ years). A friend recently let me borrow an ultrasonic cleaner and I noticed some weird velocity changes. Essentially, when I clean using the ultrasonic cleaner I am averaging 35fps increase over walnut cleaning.

I attribute this to the lack of carbon in the neck acting as a lubricant. Is this in line with what others have seen?
I saw the same thing when i briefly switched to wet tumbling. I believe you are correct in saying its due to the carbon left in the neck during dry tumbling acting as a lubricant. I switched to only dry tumbling for consistency which also gives me better ES. Which ever way you choose to clean your brass adjust your load accordingly.
 

straightshooter1

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Repeat the test in detail with only the one variable and see if the results are the same. That's really the only way to know if this is actually true.
 

Bloody_Tailgate

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Repeat the test in detail with only the one variable and see if the results are the same. That's really the only way to know if this is actually true.
That was the only variable...it's true at least with my brass. It actually caused me to shoot an additional 200 rounds during load development because of the inconsistencies it caused.
 

straightshooter1

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Is it common knowledge that cleaning brass with an ultrasonic cleaner will increase muzzle velocity? I'd never used one in the past as I always tumbled in walnut media (for 20+ years). A friend recently let me borrow an ultrasonic cleaner and I noticed some weird velocity changes. Essentially, when I clean using the ultrasonic cleaner I am averaging 35fps increase over walnut cleaning.

I attribute this to the lack of carbon in the neck acting as a lubricant. Is this in line with what others have seen?
I've not see this much difference between my .308 cases when completely clean by way of wet tumbling vs leaving the carbon in. For me, it's a significant difference in consistency regarding run out, but not much on MV's.

I'm about to run a little experiment regarding the carbon build up on a case that's been fired a number of times without really cleaning the carbon out of the case. My theory is if the carbon is not removed from the case cleaning, the carbon builds up with multiple firings and in doing so, the case volume decreases. I'm going to try and quantify this to see if there's enough build up to actually cause enough reduction in case volume which would result in higher pressures and velocities given the same powder charge. I'm not sure if it does or not, so we'll see soon.
 

supercorndogs

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Hypothises.

There will be no discernible difference from carbon build up in the case vs case volume.
 

spife7980

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I’d also like to see a batch of ultrasonic cleaned but then also tumbled to get some media dust on it. Is it the ultrasonic, the carbon or the dust?
 
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Dthomas3523

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Don’t clean it in the ultrasonic and take a brush and take all the carbon out the neck.

Also, if you’re not using pin gauges and such to check neck tension, it’s likely a moot point trying to pinpoint the exact reason.
 

supercorndogs

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If we are looking at carbon in the case reducing case volume. Would it not make the most sense to measure the H2O volume of some fired cases that are dirty and some that are clean.
 

straightshooter1

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If we are looking at carbon in the case reducing case volume. Would it not make the most sense to measure the H2O volume of some fired cases that are dirty and some that are clean.
I don't know of nor have a way of accurately or measuring with consistency the H2O volume. And over a number of firings that volume may increase as the case walls stretch and thin out. So for my little experiment, I've decided to use 5 cases and mic the neck thickness of each after each firing and record the results. Some powders leave more residue than others, so because of it's popularity, I'll be loading with Varget and will not be cleaning out the inside of the cases, but will keep them all at a constant case length and only neck size and bump shoulders. At the end of the number of firings (I'm thinking 6 or 7) and after taking the final mic measurements, I'll then measure the case's volumes. Then after that, I'll wet tumble them with SS pins until I get all the carbon out and measure the case's volumes again. It'll be interesting to me to see just what the numbers show . . . if anything. :rolleyes:
 

Steel head

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Hypothises.

There will be no discernible difference from carbon build up in the case vs case volume.
That's what I intend to find out. :cool: :)
I can show you case that finally gave up the primer pocket after 39 firings and maybe went through a tumbler 6 times in its life.
Carbon inside was amazingly light.
8EDD02F8-410A-419A-BAC1-70E2D889F06C.jpeg
 

Long Range 338

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Is it common knowledge that cleaning brass with an ultrasonic cleaner will increase muzzle velocity? I'd never used one in the past as I always tumbled in walnut media (for 20+ years). A friend recently let me borrow an ultrasonic cleaner and I noticed some weird velocity changes. Essentially, when I clean using the ultrasonic cleaner I am averaging 35fps increase over walnut cleaning.

I attribute this to the lack of carbon in the neck acting as a lubricant. Is this in line with what others have seen?
I've read that this is the case. Reportedly increases neck tension but hurts ES.
 

Muley Buck

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I use an air compressor to blow the dust out of my brass before loading.
I do the exact same thing. I use a rubber tipped air blow gun and stuff it in the primer pocket then shoot it with a quick blast and it clears the flash hole (if plugged from media) and blows out the dust as well. Works great!
 

Dthomas3523

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I can show you case that finally gave up the primer pocket after 39 firings and maybe went through a tumbler 6 times in its life.
Carbon inside was amazingly light.
View attachment 7253412
Brass has to be muddy or have a big chance of dirt/sand inside for me to clean them anymore.

I just wipe them down with a rag most of the time now.
 
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straightshooter1

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Corn or walnut, cheapest at pet store.
H4350
IMR4451
R16

winchester brass
(y)

Yeah, that carbon on the inside of that brass DOES look a lot lighter that I would have thought. I would have thought the walls of the body would have looked more like that of the neck.
 

supercorndogs

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I can show you case that finally gave up the primer pocket after 39 firings and maybe went through a tumbler 6 times in its life.
Carbon inside was amazingly light.
View attachment 7253412
I wasn't making a hypotheses. I was telling him he had a hypothesis, not a theory.

I know full well there will be no decreeable difference. I have loaded 223 brass at least 7 times without cleaning. And a difference in volume from thinning case walls. ? ? ? I have 300wm brass, at 17 I was thinking of retiring, but same load, same MV.
 

Steel head

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I wasn't making a hypotheses. I was telling him he had a hypothesis, not a theory.

I know full well there will be no decreeable difference. I have loaded 223 brass at least 7 times without cleaning. And a difference in volume from thinning case walls. ? ? ? I have 300wm brass, at 17 I was thinking of retiring, but same load, same MV.
I quoted you in agreement.
 

straightshooter1

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I wasn't making a hypotheses. I was telling him he had a hypothesis, not a theory.
You're absolutely right . . . I'll be testing a hypothesis. And the results very well may be that there's no discernible difference in cases volume. I'm just not ready to conclude that until seeing results of some kind of methodical testing done.

I've learned to be very skeptical of anecdotal evidence. ?
 
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Wheres-Waldo

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For what it is worth...

I used to conventionally tumble my brass... I switch to STM and my SD & MV increased.

Went back to conventional and my old numbers returned.

I still use STM for a few reasons, but you should lube the necks or bullets when doing so to expect comparable numbers to conventional tumbling.

Graphite, carbon, high pressure mold wax, moly, HBN, Aunt Jemima’s