Gap space, and that dirty little corner

B

Boyd Allen

Active member
The other day, I was at the range, repeatedly loading three well used 6PPC cases. I was getting frustrated. The results from a previous session were not repeating, and I could not figure out why. It is not that my groups were huge, but just that they were not what they had been. At one point, puzzled as to why, after FL sizing, the load with one case had a tight bolt close even though the bump had been set to .001, and they all had been FL sized, I checked the cases for length, and although none were over the chamber length specification (1.515) the one that was tighter was way too close. At that point I got out my Possum Hollow trimmer, and Holland VLD chamfer tool and got busy. I wish that I could say that my groups showed the difference. I left the range somewhat puzzled, and more than a little frustrated. Later, thinking over what the problem could have been, it occurred to me that I might be fighting an unusual deposit of powder fouling in the inside corner at the end of the neck part of the chamber. I had been experimenting with three different powders, and although my cleaning method had passed borescope inspection when using 133, perhaps the fouling from the other powders was more resistant. This brings up two questions. Can I get around the problem by simply trimming my cases shorter than I have been without sacrificing accuracy, and how do I get the stuff out without hurting the barrel? (This assumes that there is something there in the first place. I am going to do a normal cleaning and the n pull the barrel and look for anything that it missed in this area.)

Some years back, Mr. Boyer recommended using a nylon brush loaded with IOSSO to clean carbon from the throat and first 8-10" of the breech end of the barrel. The problem with this approach, for me. is that for those of us that buy barrels one at a time, and need to get more than 800 rounds of service life, cleaning with an abrasive every time may not be an attractive option, and given that different powders may have different fouling characteristics, may not be necessary. (old T compared to 133). Another option would be to use the same type of brush and abrasive, but use a brush one caliber larger and only work to the end of the chamber, by feel. (I think that Speedy wrote about this.) A third approach would be to wrap an old bronze brush (at the end of a chamber rod) with some 0000 steel wool, apply some light oil or Hoppes #9, and twist the rod in the chamber while applying some forward pressure. I first read that 0000 on a brush wouldn't hurt a barrel in a post by Mickey Coleman. I have tried it, and did not see any evidence of damage when I bore scoped afterwords.

Have any of you any experience in this area? Do you do anything in your normal cleaning to address this area?

Thanks
 
Geeze Boyd,
couple things come to mind:
using three pieces of brass over and over is just gonna hammer it, sooner rather than later it won't respond reliably to any die setting.
don't mix different powder fouling within a single cleaning regimen,133 dosn't like sliding over 8208 fouling,vice versa, etc,etc,etc.
three shot groups don't tell you nothin'. (Unless you want to know how your gun will behave in a three shot match.)
Iosso is the mildest of abrasives,use on a nylon brush and then be shure to flush it all out of there( I use brake cleaner followed up by my usual Shooters/kroil mix).
Get 25 pcs of good brass and rotate it through your shooting sessions. Stick with one powder between cleanings,one or two foulers then five shot groups, normal clean after 17. Iosso after about every 50-100rds.Nylon brush ,concentrate twisting in neck throat area then finish up down and out the bore.
Hope this helps,
Joel
 
Joel,
Thanks for the response. I know the limits of three shot groups, but this was very preliminary testing, and I knew that I would be running up some pressure during the test, and I don't like to hit one or two cases of a set that much harder than the rest. I learned some things. It wasn't a total waste, it is just that in considering how it went, I missed a couple of things that I want to correct in the future. Jack Neary has spoken of the advantages of having plenty of clearance and trimming often, what I ran into may be a classic example of what happens if you don't, at this point I need to take a closer look inside the chamber to see if my cleaning is missing something. I may have just gotten spoiled with 133 being so clean, and being able to get away without special cleaning at the end of the neck. I think that the next thing I need to do is to see if I have a 6.5mm nylon brush in my cleaning kit. I have the IOSSO and the chamber rod. Thanks for doing a detailed description of your routine. It helps.
Boyd
 
Boyd,
Basic rule of thumb is to keep cases trimmed at least .010 under chamber length( 1.515 in a 1.525 chamber,etc) less case length wont hurt but try for all you can get.Nothing gained by trimming to 1.480. Jack's trimming quotes are aimed at having all cases the same length so neck tension is consistant. One .010 longer case has .010 more grip on a bullet than the other four cases in your group.
On neck clearance; keep in mind Jack shoots a .263, Neck wall thickness is partly responsible for neck tension. If you shoot a .262nk or smaller chamber,getting your neck walls too thin for the sake of clearance will cost you resiliant neck tension. If your chamber neck is .263 or larger a little extra neck clearance should still allow good consistant neck tension.
Many shooters shot extremely well before bore scopes and the discovery of the dreaded carbon ring.Cleaning it out is good hygene,but from a practical standpoint it should not effect the way the gun shoots unless you have been shooting 1.480 trimmed brass and then started shooting 1.515 brass in the same chamber without cleaning the ring out.
Joel
 
Did you check the diamater of the cases at the base of the cases. I have found, with 30 BR cases, that some of them expand at the base and will be tight no matter how much they are bumped. I don't see how PPC cases can be any different in the way they react to being fired a lot. I found that by full length sizing with a Small Base die, I could restore the cases to where they worked well again. A regular Full Length die won't push the bases to the size they need to be at. It takes Small Base Dies to size cases properly.
 
Last edited:
My FL die is a Harrell Vari-Base, I have a full set of inserts. I have pretty much settled in on one that gives me a what I need, but it is always possible that I could use a smaller one to advantage on this little set of used and abused cases. I do remember that after the trimming, the bolt closed easier on the tight case, and although the case was only a couple of thousandths under 1.515, it was under, which means that either the reamer is off spec. or there was something taking up the space that should have been there, a deposit. We shall see.

One little observation, although these cases have seen hot loads in the case of my testing, the primer pocket are still serviceable.

A while back, I had a click issue with one of my test cases. The shell holder that I use has been shortened, so I was able to screw the base insert of the die out part of a turn, so that it would size just a little farther down the case, I ran the case through again, and fixed the click. I think that one of the reasons that we have a problem is that the chamber covers just a line width more than the sizing die can reach. A more expensive remedy would be to buy a custom Jones die that has the shoulder as part of the neck bushing, which is adjustable for bump without changing how far down the body of the case the rest of the die sizes.
 
Last edited:
The one thing I keep seeing here is that only one case had the problem.
You mentioned in post 7 the same thing about only one case in the group being tight.
I usually keep 50 cases going at once in rotation.
I occasionally get one that will get that so I dont think much about it being just one case.
 
If nothing else, the one thing that I have gotten out of this is that I have not made a habit of checking case length often enough. In a recent post, Lou Murdica wrote, somewhat cryptically, that the case mouth is the first crown that your bullet sees. Given his experience, I think that I will start trimming a lot more often. The one thing that I can see, from my recent trips to the range, is that I have sometimes looked in the wrong places for improvement of accuracy. There are so many small factors involved, it is easy to overlook one or more. Perhaps it all goes back to what Albert Einstein once said "The definition of insanity is doing the same thing over and over again and expecting different results".

On the tight case...it was the longest one.
 
Boyd,
You are absolutely right on track to think that 133 has spoiled you. I had some 8208 blend that would flat out shoot dot's. The problem was the cleaning it took to keep it shooting that way. I eventually decided that it was easier to "manage" my 133 loads than to keep the barrel clean using that 8208. That decision had more to do with my desire to enjoy shooting matches than my desire to win them. I was amazed by the carbon build up just in front of the case neck when shooting the 8208.
Russ
 
I am far from having the experience that many of you have posted have but this is what I have read and heard from some of the names mentioned. Are they fact or fiction? I have NO idea, but I want to believe that there are shooters out there who are HONEST when they say things.

In regards to trimming case lengths, Jack Neary mentions MORE is better. If I am not mistaken he mentioned in Kansas in 2010 he trims to 1.490. He found the case growth to be more manageable when trimmed to that length and I THINK the growth was not as fast. He trims after every day of shooting. I have since followed that routine even though I would rather be in front of the bar instead of trimming. It is a price we pay to play.

In the same session he mentioned to turning necks to a total clearance of 3 Thousanths. If I am wrong on this someone will or Jack may correct me.

In regards to the nasty carbon ring and what Tony talks about in his book using one brush larger with IOSSO and spinning it in the throat area, I can believe it. Why? Just look what the trend is. A GOOD fitting bore guide to not damage the throat and protect the barrel as best we can. What does that GOOD bore guide prevent? It prevents the solvent and brush from coming in contact with that NASTY carbon ring that possibly builds up and causes grief. Why should it form in the first place? Our cleaning techniques have proven to remove the carbon from the length of the barrel so why not the throat area. The only thing I can see is the TIGHT fitting bore guide.

What I think needs to be done is as Tony says but done as part of every cleaning routine. The trend is wet patches first then the brushing. After loading the wet patches drying and some sort of oil.

I think I need to go back to what I used to do. Wet patches, brushing, remove bore guide, spin cleaning brush with solvent in the throat area,let soak while loading. After loading spin brush a few more times, reinsert bore guide, wet patch, dry, then oil. To make sure there are no pieces of carbon in the throat area use your bore mop with a patch and some camp fuel in the chamber then use your lug recess tool to make sure there is no crud in them.

I am even uessing if the bore guide was pulled back slightly to give the bristles of the brush time to spring outward there would be less if no carbon rings.

But, what do I know. I am not in the position to experiment I am just a follower.

In regards to what the XBR 8208 was supposed to be, I hate that stuff and am sorry I bought some. The cleanest stuff I have shot in my PPC's is 133. The dirtiest at any load was XBR. Sorry to those of you who have had success but it is DIRTY SH++.

I hope the LT-32 and or the 2015 is what Lou says it is and that AA will deliver for years to come. I cannot wait to try it.

Unfortunately for a product that is manufactured in Canada we cannot get it right away. It is shipped States side to be rebottled and sold back to us. Oh yah and it has to be approved by the Government before it can be brought back. What a load of Cr+P.

Anyways just my take on that dreaded black ring.

Calvin
 
I just wanted to clarify that when I said 8208, I was talking aboput the pulldown 8208 we were getting back in the early 90's. If anyone is really duplicating T powder then you will need to be aware of what comes with it (it leaves more carbon than 133!). Now that being said, the best T or 8208 was worth the trouble if you really wanted to shoot small. I just want people to know that you can't clean like its 133 or you are going to have trouble. A bore scope will tell the tale!
 
Here is what I did today. My barrel had been cleaned and well brushed not too long before I shot the last few rounds before leaving the range, so I did not think that there was much in the bore. To address what I have called the "dirty little corner" i put an old 6mm brush on my Sinclair chamber rod, and wrapped its end with a patch that had had JB worked in from its leading edge, to about 1/3 back. I wrapped the patch around the end of the brush so that it was a little forward of the looped end of its brass core, and then applied a little more JB. Carefully inserting the brush through my rod guide, I was able to feel a definite stopping place at the end of the chamber neck, and while maintaining forward pressure, turned the what little of the rod was sticking out of the back of the guide with my thumb and forefinger, perhaps 10 full turns. I then removed the rod, which showed some carbon/powder fouling (?) on the patch, wrapped a clean patch on the brush, and wet it with BBS, inserting, and twisting as before. After that I short stroked four wet patches through the barrel. The last two came out clean. At that point the bore felt smooth all the way. I then dried the bore, and the chamber, lubed the bolts locking lugs and cocking cam, and called it quits. I think that I will start using this method on the front of the chamber, when I clean, as long as I am experimenting with something other than 133....just as a precaution. This, combined with staying on top of case trimming, should keep me out of trouble...in this area....I hope. It will be interesting to see how my next rang trip goes, as soon as the storm cycle stops for a while. All this rain is holding me up. What with our only being 40% below normal rainfall for this time of year, , with an average total rainfall of around 12", a quarter inch storm feels like a deluge;-) That should amuse all of you that have web between your toes. My cousin in northern Louisiana tells me that they average around 48" a year. I don't think that they even know what a lawn sprinkler system is.
 
Last edited:
FWIW
I did a test last year on several carbon removers.
Liquids and pastes. What I found could be causing false readings for a lot of people.
You can test it yourself.
I found that certain products will sort of react with the barrel (SS) and turn black regardless whether it is dirty or not.
To test yours simply clean the outside of the barrel with alcohol then take your preferred cleaner on a patch and rub the clean area of the barrel with the same force you use to clean the inside of the barrel.
You will be surprised how many patches can turn black even from clean steel.
Kind of like using brasso on clean brass can still turn the rag black.
Try it for yourself...
 
Vern,
Thanks for reminding me. I am familiar with what you mentioned, but a reminder never hurts. Did any of the liquids pass muster? I have tried Carb-Out a few times, and it has removed some stubborn black, but as to its composition (what I removed) I am not positive that it was the hardest of carbon deposits, or just a deep buildup of more ordinary powder fouling. What were your results?
 
Boyd at the end of the season last year when I did the test I found that one called Seafoam seemed to cut the carbon really well.
It also tended to turn the patch gray when rubbing it on the outside of the barrel, gray but not quite black.
This year I have been soaking the barrel and front chamber area with a couple of wet patches while I reload. I go back brush with it then just for peace of mind I use a little Eliminator for the copper just in case. When I bore scoped it there was not carbon ring.

The black test I did equates to trying to determine if you have copper while using eliminator with a bronze brush.....

What I hope to do in the near future is to gather the carbon from the primers when I resize and from any other realistic place and place some in containers and just simply put a little of some of the various solvents and see which can actually break down the carbon and which dont.
I want to try the same thing using some copper from bullets and some of the cleaners like eliminator, wipeout and the like and see what the actual result is in "dissolving" the copper....
I sometimes think the copper "removers" have a few more unknown variables that we attribute to their success.
Such as if a particular barrel doesnt copper up or how one guy brushes with 5 strokes when another uses 15-20.
While I am at it I think I will mirror up the outside of a barrel and just drip some of the cleaners onto the barrel and let them sit overnight wrapped in plastic to see what affect it has on the metal of a barrel.
In other words if it is strong enough to dissolve copper what can it do to a barrel?

Has anyone else already tried these types of experiments?
 
Take a scrap case that exceeds the chamber length by couple thousands. Turn or size OD of neck to fit snug in chamber. Use a vld tool and sharpen the case mouth. Chamber case to scrape carbon ring away.
 
How do you get the case to turn so that it will cut the carbon?
Closing the bolt does not always cause the case to turn.
 
As the case slides in, it scrapes the carbon. Does not need to turn. If you want it to turn, maybe drill out the flash hole big enough to accept a screw and attach it to a chamber swab tool.
 
You must log in or register to reply here.
Back
Top