switched cleaning methods - ES/SD improves, why?

[hkfan45]

I was using a wet stainless media cleaning system (Thumbler Tumbler) and recently had to quickly load some fired brass for a range trip. Since I didn't have time to run the brass through the tumbler, I placed each case in my lathe and used 0000 stainless steel to clean outside of case. I ran a nylon bore brush in the case mouth, and cleaned the primer pockets. When seating the bullets, I noticed that the seating pressure was much more consistent than when I seat bullets in brass that has been wet cleaned.

Well, that must have did the trick since my ES/SD improved significantly. SO, my question is, why clean brass with wet stainless media, if just cleaning the brass by hand seemed to be faster, less messy, and resulted in more consistent bullet velocities? Does leaving carbon in the neck actually improve accuracy? Is cleaning brass to the point that it looks like new overrated?

 

[LRShooter101]

The answer to your question could be your Neck Tension.

Couple of issues with Neck Tension:
How "hard" is the brass?
How consistent is the neck thickness?
How consistent is the sizing process?

The more brass is "worked" (cleaning, sizing, etc), the harder it gets, and the less consistent the neck tension will be. "Wet Cleaning" may harden the necks on the brass. IMHO, if you are going to run the brass through multiple cycles of shooting and wet cleaning, then you will need to anneal it after 2-3 rounds to try and keep the necks from getting to hard.

Your changes in cleaning process may also lead to some variation in the neck tension/bullet release.


Beyond your situation with "Wet Cleaning", in terms of Neck Tension in general,
Depending on how you resize the brass, varying neck thickness can impact the neck tension.

Not sure what type of Die that you are re-sizing with, but based on the type of Die and setup, there are certain things that can be done to insure neck tension is consistent. It amazes me the number of people that size only with a neck bushing, or an internal expander, and expect consistent neck tension? Contrary to popular belief, both internal and external neck measurements can be critical, and only working one of them, will not necessarily guarantee the other. You might want to check the consistency of the neck thickness in your brass, and that is all around the neck of a single case, as well as from piece to piece. If you have any level of variation, then it can lead to issues with neck tension (and runout), both of which could impact accuracy. How much, obviously depends on how bad the variation is.


I am anal about checking neck tension on my loads using Pin Gages after they are re-sized.
https://www.youtube.com/watch?v=JMxS3eBtko0
This insures that the internal diameter, and resulting tension on the bullet is as consistent as it can be. I run all of my precision loads with .002" of neck tension. So for a .308, I insure that all of my necks have an internal diameter of .306.

You can also use a gage or micrometer to measure neck thickness and then sort the brass for consistency.
Redding Case Neck Gage w/ Indicator | Sinclair Intl


Only real way to deal with varying neck thickness, is to measure and sort, or neck turn it all to consistent thickness. There are obvious pros & cons to both options.

If you check with the guys setting and braking shooting records, they will tell you that neck tension is a major player when it comes to getting the absolute maximum performance out of your ammo.

 

[Bill Larson]

accurate SD/ES numbers are hard to obtain.........I use an Ohler 35P ( supposedly good unit )...and a magneto speed......load up 20 of your best rnds.shoot groups 5 different days ...approx. same conditions...... take average.....otherwise.... you`re just approximating.....

 

[hkfan45]

The answer to your question could be your Neck Tension.

Couple of issues with Neck Tension:
How "hard" is the brass?
How consistent is the neck thickness?
How consistent is the sizing process?

The more brass is "worked" (cleaning, sizing, etc), the harder it gets, and the less consistent the neck tension will be. "Wet Cleaning" may harden the necks on the brass. IMHO, if you are going to run the brass through multiple cycles of shooting and wet cleaning, then you will need to anneal it after 2-3 rounds to try and keep the necks from getting to hard.

Your changes in cleaning process may also lead to some variation in the neck tension/bullet release.


Beyond your situation with "Wet Cleaning", in terms of Neck Tension in general,
Depending on how you resize the brass, varying neck thickness can impact the neck tension.

Not sure what type of Die that you are re-sizing with, but based on the type of Die and setup, there are certain things that can be done to insure neck tension is consistent. It amazes me the number of people that size only with a neck bushing, or an internal expander, and expect consistent neck tension? Contrary to popular belief, both internal and external neck measurements can be critical, and only working one of them, will not necessarily guarantee the other. You might want to check the consistency of the neck thickness in your brass, and that is all around the neck of a single case, as well as from piece to piece. If you have any level of variation, then it can lead to issues with neck tension (and runout), both of which could impact accuracy. How much, obviously depends on how bad the variation is.


I am anal about checking neck tension on my loads using Pin Gages after they are re-sized.
https://www.youtube.com/watch?v=JMxS3eBtko0
This insures that the internal diameter, and resulting tension on the bullet is as consistent as it can be. I run all of my precision loads with .002" of neck tension. So for a .308, I insure that all of my necks have an internal diameter of .306.

You can also use a gage or micrometer to measure neck thickness and then sort the brass for consistency.
Redding Case Neck Gage w/ Indicator | Sinclair Intl


Only real way to deal with varying neck thickness, is to measure and sort, or neck turn it all to consistent thickness. There are obvious pros & cons to both options.

If you check with the guys setting and braking shooting records, they will tell you that neck tension is a major player when it comes to getting the absolute maximum performance out of your ammo.

Thanks for the helpful information. My case prep process remained the same, with the exception of the cleaning method (wet vs merely cleaning outside of case). It might have been too small a sample, but I did notice the brass where the inside of the neck wasn't cleaned had more consistent seating "feel." I'm just wondering if the benchrester's who reload at the bench with no time to clean cases are on to something re: carbon in the neck. I find case cleaning with the tumbler a hassle and want to know what I am really giving up if I avoid it and merely clean the outside of the case.

 

[InfScout1/69]

If you don't clean inside the case... You case volume will change by carbon build up.eventually and throwing off pressure reading... May not be enough to see the sufferance or not?

 

[Svendogg]

I'm going off wild internet rumors here so don't flame me if I'm all out of whack, but I have heard that both ultrasonic cleaning and S.S. Media (wet) cleaning can cause the necks to become "grabby". Essentially cleaning off the slight carbon layer on the case mouth that actually reduces friction. One way to resolve this that I have heard and tried (although did not test) is brushing the inside of the neck with graphite powder. Forster actually sells a case neck graphiter ($20?) specifically for reducing/evening out this friction. I'll try to do some testing to see if there is any reduction in my SD's, but won't be able to do it for a few weeks. Hope some of that helps, definitely interested in what you find out!

 

[jsthntn247]

I'm going off wild internet rumors here so don't flame me if I'm all out of whack, but I have heard that both ultrasonic cleaning and S.S. Media (wet) cleaning can cause the necks to become "grabby". Essentially cleaning off the slight carbon layer on the case mouth that actually reduces friction. One way to resolve this that I have heard and tried (although did not test) is brushing the inside of the neck with graphite powder. Forster actually sells a case neck graphiter ($20?) specifically for reducing/evening out this friction. I'll try to do some testing to see if there is any reduction in my SD's, but won't be able to do it for a few weeks. Hope some of that helps, definitely interested in what you find out!

This is exactly right. Take some ultrasonic cleaned brass or stainless tumbled brass and some that have just been outside cleaned. Seat all them on a k@m or 21st century press with seating force attachments and it will be easy to see the differences. Then take some of the ultra or stainless cleaned brass and coat the inside of the necks with graphite or whatever lube you want and seat them with the gauge press and you will see a world of difference. They all have the same "tension" the grip is what is different. I prefer ultrasonic cleaning them then adding lube to the neck so I can makes sure I add the same amount of lube to each one. If you shoot the same piece of brass over and over without cleaning the neck with anything, the carbon layer will build up and increase tension also. Neck tension will make you loose your damn mind until you get a sequence down that works for you and do it the exact same way everytime.

 

[Powermac]

Yes cleaning can make the cases more grippy, as friction is reduced. Graphite powder and the like will help, neither is it messy or contaminates powder.
Imperial dry neck lube and media applicator is what i use for it,works like a charm, and less messy then brushes tends to be, and seems to give a more sparingly and even application.

It does help reducing seating pressure and make it more uniform, i have tried it with my arbor press once when making the decision of using it or not.
From my findings 25-40 PSI on my hydro bullet seater seems to give me the lowest SD/ES numbers in my rifles though.
So if the reduction in seating pressure will give any effect and witch i can not say, but more uniform seating pressure and neck tension normally gives lower es/sd to a varying degree.

Leaving the brass dirty and uncleaned is certainly not the way to go, and yes internal volume will change minimally and you might loose your gained es/sd from it with cases fired many times at least in theory, never tested it.
It also gunks up any tools you use inside the case, as expander, decap assemblies, expander mandrels, turning arbors etc.
You also want to clean the primer pockets for sure and preferrably flash holes.

Yes wet tumbling is a bit messy, but works a lot better then the other methods and i prefer to do it over Ultrasonic for sure.
Dry tumbling is not without mess either.

I would suggest to the OP that you try a box of Imperial media applicator and continue to clean your cases in a proper way and see what your results are, i am fairly certain you find you gain nothing by not cleaning your cases except from a few dollars.

 

[427Cobra]

The simple truth is, dirty brass shoots better than ultra clean brass, the outside needs to be cleaned to protect dies, a quick pass with a Krazy Klothe or 0000 steel wool is all that is required, a quick in, turn, pull out of a worn bore brush is all the inside of the neck needs, the left over carbon inside the neck provide a barrier between the brass and copper jacket which aid in bullet release, I still clean my primer pockets even though I'm starting to think I can't shoot the difference, I still use SS media, but only to clean range brass that I shoot thru my pistols and ARs.

 

[hkfan45]

The simple truth is, dirty brass shoots better than ultra clean brass, the outside needs to be cleaned to protect dies, a quick pass with a Krazy Klothe or 0000 steel wool is all that is required, a quick in, turn, pull out of a worn bore brush is all the inside of the neck needs, the left over carbon inside the neck provide a barrier between the brass and copper jacket which aid in bullet release, I still clean my primer pockets even though I'm starting to think I can't shoot the difference, I still use SS media, but only to clean range brass that I shoot thru my pistols and ARs.

Thank you for posting this to support my theory. This is exactly how I clean the brass. After 0000 steel and krazy Kloth, the brass looks brand new from the outside. I know German Salazar doesn't believe in cleaning other than by this minimal process. I am concerned about case capacity decreasing over time though.

 

[427Cobra]

I belong to the same Gun Club as the man who shot a .007 group at 100, I watched him over and over again load 5 pieces of brass, shoot a zero group(5 shots that measure .0--), all Mike does is hand clean his brass, brush his neck, brush his pockets, FL resize, yes he FL every time, throw a charge, in comps his charges are pre weighed using a big dollar lab scale and stored in vials, seat and shoot, another club member who is on the US F-Class Team does almost the same process except he anneals his cases every time. Carbon inside the neck is a good thing, big chunks of it are a bad thing for concentricity.

 

[DocB]

hkfan45,

Getting an internal neck finish to a consistent place helps a lot. Try cleaning the brass with US or pins, then make the internal necks consistent by running 4-0 steel wool in the necks after trimming, deburring, etc.

HTH,
DocB

 

[bigedp51]

This topic has been discussed many, many times at accurateshooter.com Reloading Forum (All Calibers), and I want you to think of galvanized steel and the zink coating giving up it positive electrons that transfers to the steel to prevent corrosion.

Now think of the ultra clean stainless media cleaning the inside of the case neck gets down to bare metal, now think of the bare copper bullet transferring it positive electrons to the inside of the case neck.

Now think of the Uniroyal tire commercial for their Tiger Paw tires that "grip" the road.

One of the Accurate Shooter forum members seated bullets using three different case cleaning methods and then tested them after letting them sit for a given times. The stainless media cleaning required the highest force to move the bullet in the case neck, and this force increased over time.

The carbon in the uncleaned case necks prevents the bullets from bonding to the inside of the case neck, after this the engineers started arguing over the plating theory and dissimilar metal corrosion theory.
(its a sticky subject)

 

[supercorndogs]

i had the same problem. i started to use a lee collet die after i tumble my brass and that took care of it. i have read that tumbling brass will deform the mouth and make it smaller. i tumble with corn media. for the price of a collet die it is worth a try. i have lower sd using it on my 223 308 and 300wm then when i full length

 

[bruddah]

I belong to the same Gun Club as the man who shot a .007 group at 100, I watched him over and over again load 5 pieces of brass, shoot a zero group(5 shots that measure .0--), all Mike does is hand clean his brass, brush his neck, brush his pockets, FL resize, yes he FL every time, throw a charge, in comps his charges are pre weighed using a big dollar lab scale and stored in vials, seat and shoot, another club member who is on the US F-Class Team does almost the same process except he anneals his cases every time. Carbon inside the neck is a good thing, big chunks of it are a bad thing for concentricity.

Interesting.

 

[mdmp5]

I tumble in stainless media for the last 5 years or so. I only tumble for less than 2 hrs, and there is a slight carbon residue inside the mouths. The mouths never come out sparkling.

 

[bruddah]

I tumble in stainless media for the last 5 years or so. I only tumble for less than 2 hrs, and there is a slight carbon residue inside the mouths. The mouths never come out sparkling.

Good to know as I also just bought a S/S media cleaner.

 

[Mad_Charlie]

The simple truth is, dirty brass shoots better than ultra clean brass, the outside needs to be cleaned to protect dies, a quick pass with a Krazy Klothe or 0000 steel wool is all that is required, a quick in, turn, pull out of a worn bore brush is all the inside of the neck needs, the left over carbon inside the neck provide a barrier between the brass and copper jacket which aid in bullet release, I still clean my primer pockets even though I'm starting to think I can't shoot the difference, I still use SS media, but only to clean range brass that I shoot thru my pistols and ARs.

I agree completely.

 

[dmike]

The carbon in the uncleaned case necks prevents the bullets from bonding to the inside of the case neck, after this the engineers started arguing over the plating theory and dissimilar metal corrosion theory.
(its a sticky subject)

What do manufacturers of new factory match ammo do to mitigate this? Their ammo can sit for years and still shoot sub moa. I understand br guys are going for much greater consistency but do mfrs do anything to prevent this phenomenon with their new (clean?) brass?

 

[Mad_Charlie]

If you don't clean inside the case... You case volume will change by carbon build up.eventually and throwing off pressure reading... May not be enough to see the sufferance or not?

How many times will the case need to be fired with something like 748 before you see a half grain difference in h2o capacity, assuming a .308 case?
I am willing to bet that the case will be history before it makes much difference.

 

[Mad_Charlie]

What do manufacturers of new factory match ammo do to mitigate this? Their ammo can sit for years and still shoot sub moa. I understand br guys are going for much greater consistency but do mfrs do anything to prevent this phenomenon with their new (clean?) brass?

They don't do anything, a lot of folks "bump" their seating depth a couple thou if their ammo has been sitting around for a while.

Load your match ammo, and go shoot your match.

 

[Victor N TN]

I think it isn't whether you clean surgically clean or leave them dirty. But the key is to do everything the same way every time. If I don't clean my case necks with a bronze / brass brush every time I get grabby necks. I started cleaning inside case necks shooting benchrest. But now it's carried over to all my other rifle loads.

 

[denobravo]

Somewhere..someone did a test with carbon residue in the necks...
Does anybody remember reading it ?
Ive been internet seaching for a while now, might have been a magazine article.

I may be getting better ES with clean necks because I shoot BN bullets and the bn acts as a release agent...I dont know.
I am on a bit of a quest to find empirical evidence. This aspect of launching a projectile has me a bit fascinated.
How can somthing so simple remain a mystery to so many scientists. It should be easily proven. I however do not have the expertise to create and prove either way.
It seems clean necks are not consistent, (all things the same) even though they should be the most stable group.
Please if you have seen the test on carbon, let me know
THANK YOU

 

[Long Range 338]

This may be the article you mentioned. I've been going to try this myself but haven't got to it yet.

https://www.primalrights.com/library/articles/clean-brass-with-rice

 

[918v]

Your ES/SD improvement is due to the difference in neck surface. Your cleaning solution/cocktail must have been incorrect and caused acid etching and subsequent galling/neck weld.

Correct ratios of soap to acid prevent this sort of thing.