cleaning inside case necks of carbon

  • Last Post 13 January 2021
fa38 posted this 08 January 2021

What is the best or easiest way to clean the inside of case necks of carbon residue?  I hate cleaning the case necks.

I was using my Lee collet die on some relatively new ppu 7 mauser brass and I collapsed the shoulder of one of the cases .I could feel a lot of resistance to the case going into the die so I tried a different case which sized normally.  I ran the case with the resistance and collapsed the shoulder. Crap

I ran some more cases into the die and felt a lot of resistance on another case.  I then cleaned the inside of the case neck with a cleaning brush until I could see brass all around the neck inside.  I ran it back into the die and felt no resistance and it sized as it should.  I had a third case that did the same and with cleaning it sized normally.

I did feel a slight resistance on some of the other cases but not enough to get my attention like the one I collapsed the shoulder on and the other two I cleaned. I think the decap rod is what is giving me the resistance and after taking the rod out it showed no buildup of anything.

I have been shooting 9.1 grains of Win 231.  Maybe this powder puts a lot of carbon on the inside of the case and or case neck.

Therefore, what is the easiest way to clean inside necks?



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Tom G posted this 08 January 2021


The best way I've found to inside clean case necks is to use a brass bore brush mounted in an electric drill and simply run it in and out of the case until you see a nice clean surface in there. It really doesn't take long to do and will allow you to make more uniform reloads and not damage the brass.  

I shoot mostly pistol ammo now with my powder coated cast bullets. I don't have to clean case necks as the case polishing process I use now gets the inside of the cases looking like they have never been fired yet. What I do now is use small ceramic pellets as the cleaning media and use a solution of water, citric acid and dawn dish detergent to clean the brass. I just put enough pellets in the vibrator case cleaner to cover up the brass and let it run about 2 hours. Then I sift out the pellets to be used over and over again. I rinse and dry the brass and it looks like brand new brass inside and out and don't have to worry about carbon in the necks. 

About 8 or 10 years ago I was competing in a varminter type match where you shot from 200 to 600 yards at berms that were at 100 yard intervals. I was shooting a 6 Ackley with Tubbs bullets. These bullets were lead but were wearing copper condoms.  I could shoot 6 inch groups at 600 yards with brass loaded with carbon in the necks prone with a bi pod. 

Since I suspected that my vertical dispersion was being effected by different amounts of friction in the necks I made a gauge to measure neck pull in each case.  My goal was to sort out or match up all my cases so that they had the same amount of friction on the bullet as it left the cast during firing. The gage was built sing a B Square arbor press where I mounted a 6mm dia. polished stud that could be inserted into the case necks to the same distance each time and then measure the force needed to pull the stud out of the neck. This allowed me to measure the neck pull and sort out the brass by neck pull tension. All cases had necks turned to .012" thickness but had different numbers of firings on them and different amounts of carbon built up in the necks. 

My testing showed that, on my scale, some cases measured as low as 20 and some as high as 80 or 100 to extract the stud from the neck.  I.O.W. big differences in neck pull between the cases I was using. Seeing this, I decided to not try to match up them for batches of the same tension but to bring all the cases back to the same condition on the inside of the necks prior to reloading them. I did this by cleaning all the necks each loading cycle back to a clean surface which was the most consistent condition I could achieve. 

It worked!!  My verticals at 600 yards went from 6 inches to 4 inches. I also matched up all the cases to the same neck pull for the 500 yard and 600 yard stages of the course.

One thing that I learned from measuring neck pull was that carbon in the necks increased the friction required to pull the bullet out by, on average, doubling the force necessary to pull it out under a static condition. If the mean force for clean necks was say, 40, it would take 80 units of force to pull the same polished .244" dia stud out of a carbon fouled neck. 

In summary, you can probably fix your problem by cleaning each case neck by abrading the carbon off using a brass brush or you can do it in the case cleaning process by using some sort of media that will abrade it off the necks that way.  

The media I'm using was given to me by one of my sons who was working for a company that built shot peening and de burring machines for the industry. The little ceramic pellets are in two shapes. Some are round and about .200" in diameter and the others are in the shape of a cylinder about .300" long and .075" in diameter. These have the ends cut off at a slant to provide a sharp end to abrade the material they are being used on. Neither one seems to cause any problems with bridging inside the cases except for maybe one in 500.  So, I do have to check each one before sizing them just to be sure they are clear inside.  Other shooters that I know use small steel pins that are available through normal suppliers for reloading equipment. They seem to work just as well as the ceramic media my son provided. One advantage of using steel pins is that they can be easily collected by using a magnet and never wear out.  

Your mileage may vary.   


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BigMan54 posted this 08 January 2021

For me, I've always used a dry case neck brush. Then a lubed brush. For .223 & 308/.30-06; I have the Redding Carbide Size Buttons. No Lube is needed, you would have to switch to a Redding setup for that.

60yrs ago My Dad used a Piece of #OOOO steelwool wrapped around a piece of heavy wire to clean/polish the inside of case necks for the .222Rem.


All I got..... 

Long time Caster/Reloader, Getting back into it after almost 10yrs. Life Member NRA 40+yrs, Life S.A.S.S. #375. Does this mean a description of me as a fumble-fingered knuckle-draggin' baboon. I also drool in my sleep. I firmly believe that true happiness is a warm gun. Did I mention how much I HATE auto-correct on this blasted tablet.

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fa38 posted this 09 January 2021

Thanks Tom and bigman.  I am using a bore brush which gets the carbon but I was hoping for an easier method.   

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Tom G posted this 09 January 2021

You can probably speed up the neck cleaning if you take your bore brush and wrap it with 4-0 steel wool or bronze wool.  When the brush starts to wear you can make it cut again by adding some wool to it to make it tight again.  A few years ago, I was able to buy some e bronze wool from a local hardware store.  They had to order it for me but it came in within a week. They had different grades and I would recommend the fine grade of wool.  Bronze wool will remove the carbon safely and not damage the brass necks.  It is great for removing any leading from a barrel too. Works real fast.  


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4and1 posted this 10 January 2021

I use Never-Dull on outside and inside of necks. I clean then right after firing, pull a small wad from the can, clean all the outsides, then pull a thin layer and wrap it one a worn brash and turn inside the necks. If you start this with new brass, it's easy. I used to use 4-0 steel wool, but over time I think it does cause some wear on the brass. Most of my brass is turned necks and use a bushing die for resize. With no carbon layer, seating bullets has a nice feel to it, and I can tell variances in seating pressure.


I was told long ago, the brass case is the first "crown" a bullet sees. Consistency matters.

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John Alexander posted this 10 January 2021

I didn't want to get in on this thread. Perhaps because of fatigue from reading about the recent national politics. But I can't stand all these posts about the virtues of clean necks and uniform neck tension since I believe this has been well proven to be a waste of time, I can't resist making a couple of short comments.

Jerry Bottiger ran a very well planned, well controlled, and well executed set of experiments reported in TFS # 224 (July/August 2013) that showed conclusively that variations in neck tension had no effect on EITHER muzzle velocities or accuracy (Gerry's test groups were mostly in the 4's and 5's.) 

As far as I know there have been no similar tests to question his results. They have, however, been almost totally ignored in favor of the conventional wisdom that neck tension variations naturally affect accuracy -- "it's just common sense."

I reviewed Jerry's work in an article in TFS #240 and suggested a simple and crude math based theory to explain why neck tension variation has no effect.  The short version of the theory is that the variations in neck tension force to resist bullet movement are so tiny compared to the the huge variations in the force moving the bullet (unavoidable variations in chamber press x area of bullet base) that the former tiny variation is in the round off error of the later force. I think anyone who examines these numbers and reflects on them a bit will agree that variation in neck tension is unlikely to be one of the factors we should worry about. 

As far as the idea that "the brass case is the first crown that the bullet sees", Dr. Mann showed 117 years ago that the crown has little or no effect on accuracy. His work, like Bottiger's has mostly been ignored. I reviewed Dr. Mann's work, as well as several other unsuccessful attempts to show that gross crown defects degraded accuracy in TFS #230.

I have no quarrel with shooters who like to polish necks.  But until someone shows that it improves accuracy with a well controlled experiment, I don't think we should tell others that it improves accuracy.

I realize that clear disagreement with the firmly believed procedures of others is always at risk of sounding aggressive and I am not a skilled enough writer to be sure I can avoid that.  I don't intend for my disagreement to be disrespectful toward other shooters and welcome evidence that I am wrong.



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fa38 posted this 10 January 2021

Fm: Mr. Alexander-----I didn't want to get in on this thread. Perhaps because of fatigue from reading about the recent national politics. But I can't stand all these posts about the virtues of clean necks and uniform neck tension since I believe this has been well proven to be a waste of time, I can't resist making a couple of short comments.----  

I really don't care if the neck tension varies, all I want is to be able to use the LEE collet die without collapsing the shoulder of the case.  My 30-06 cases exhibit the same resistance or drag on some of the cases when using the Lee collet die and when the first case has a collapsed shoulder I will have to clean all of them and there hundreds of them.

I am going to purchase some or the ceramic beads and try them in my case vibrator.

This is not to criticize Mr. Alexander's post as I agree about neck tension. 



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John Alexander posted this 11 January 2021


It is fair enough to criticize me, I am guilty of contributing to the discussion going far away from solving your original problem and debating whether uniform neck tension improves accuracy.  I should have stuck to solutions to the problem you presented if I had a different solution to offer.  I apologize.

In fact I do have s different solution to offer. I have used Lee Collet dies on several calibers and have never encountered the problem you describe. If I had, I would have reduced the diameter of the mandrel to avoid neck contact.  I have found that forcing the neck against the mandrel, as instructed in the Lee instructions, isn't necessary to achieve very uniform inside neck diameters if the neck thickness and work hardening  doesn't vary too much from one case to the next. Since you state that you hate cleaning case necks, this solution would avoid that chore.


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RicinYakima posted this 11 January 2021

I clean case necks because I use a Wilson seater die. Unless the necks are clean, in and out, the bullet fit is too tight to hand seat the bullet. Trying to avoid using an arbor press to mash the soft lead bullet into the minimum clearance case.

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fa38 posted this 11 January 2021

I had a 30-30 1.5 inch case chambered in a Ruger No.1 where I had the problem that RicinYakima describes.  My seater was a Neil Jones micro adjustable tool. I had turned some of the case necks so that there was a shelf on the inside after firing forming while most were just turned to .012 neck walls.

I would practice offhand shooting with 5 cases with a re-de capper, powder measure and the Jones seating tool. If I was shooting Win 540 the neck would be good for quite a few shots and the carbon would build up to the point that while I could seat the bullet I could not get the cartridge into the rifle.

 I then tried IMR SR4759 in that rifle.  The case necks stayed a lot cleaner but that powder would build up carbon in the bottom of the case to the point where you could not de cap the case.  Putting a screwdriver into the bottom of the case and giving it a good smack would dislodge the carbon.  Very thick chunks.

I was shooting more than 300 rounds a week in offhand practice at that time.  The rifle is long gone to Mr. L. Smith.

I have a 25-20 Win rifle that I shoot with Win 540/HS6 and it also carbons the neck so that when I tried to shoot fixed ammo I could not get the case into the rifle.  So I gave up trying for fixed ammo for the Hudson match at the ASSRA shoots in Indiana.  I breech seat for that rifle.  I should probably try 4759 in a couple of 25-20 cases to see if I can get it to build up carbon at the case bottom.

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Ed Harris posted this 11 January 2021

I clean case necks routinely, but don't brush. I simply use a cotton bore mop appropriate for the caliber, wipe the inside of the case neck with Ed's Red, roll the brass on a lightly oiled pad and FL size them.  After sizing they go into clean corncob to tumble a few hours which removes the lube inside and out.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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JeffinNZ posted this 11 January 2021

How about an ultrasonic cleaner.  They work miracles.


Ultrasonic brass cleaning. | Cast Bullet Association

Cheers from New Zealand

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RicinYakima posted this 11 January 2021

 Jeff, it works great but is a really slow process when trying to do 200 30/06 cases in my little Hornady cleaner. That would be about 8 hours of run time. However I do use it for the .35 Stevens cases, all five of them, after a day of shooting breach seated black powder. Ric

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Ed Harris posted this 12 January 2021

My large economy sized Dillon tumbler holds about 300-400 .30-'06 cases at a whack.  The Ed's Red swab softens the fouling and any residual Black Lucas in the necks of once-fired military cases.  It also eases passage of the expander button if you size and expand in one operation.  But for cast bullets I generally don't, preferring instead to decap with the Lee Universal, then sorting brass by headstamp and putting aside any with GI crimps which need to be swaged.  I then FL size and tumble in clean corncob afterwards.  After about 4-5 delubing uses the corncob is segregated for use in cleaning range dirt and dirt off fired brass before further processing. 

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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Shopdog posted this 12 January 2021

Bought a corded Hitachi 3/8 drill motor off evilbay on the cheap. Apparently they are refurbished?

Nice drill actually. Anyway,where the side handle is sposed to mount I fabbed up a weldment that utilizes this hole to be bolted to the bttm of a pullout shelf on loading bench.

It has an easy to reach locking handle that allows the drill to spin on the mount,presenting the keyless chuck out where it's accessible. In it goes a variety of accessories. One of which is bore brushes with bronze wool wrapped in it.

So easy. When not in use,unlock it and spin it out of the way. Liked it so much,went and bought another one to use as a handheld "twin". Corded because they are never moved. Can't post pics on this site but if you PM me,can send you some.

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4and1 posted this 12 January 2021

Long range benchrest shooters strive for the smallest extreme spread in velocity they can get, and they get that into single digits. A lot of factors come into play, but they do not ignore the necks. Many do clean the cases via ultrasonic cleaning, to remove scale from the inside. Neck thickness and tension are a big deal to them as well as keeping the length the same. Bart Sauter (Barts Bullets) has a case annealer going all the time when he is at a match, and anneals each case every firing. All of the above is to have the same bullet tension and release.

This is way more than most will consider doing, but they do get low ES. 

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Ross Smith posted this 13 January 2021

fA38: I had a similar problem with some of my 30-06 loads. Been loading 30-06 since 1970, thought I knew how to do it. I had hard or impossible to chamber rounds. I finally discovered that my problem was the case shoulder was being "blown out" during the bullet seating operation and the solution was to raise the die slightly so it was not forcing down on the neck/shoulder during seating/crimp. RCBS dies. Operator error on my part during the set-up of the die.

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