What caused a ring of lead?

[elginrunner]

https://i.postimg.cc/KYRYP2dq/IMG-20210307-142404.jpg (https://postimages.org/)

I had these fall out of my rifle after a hard to open bolt. No excessive pressure signs on primer. It's the 308-165-sil bullet in a 308. Neck sized only brass, the boolit is gas checked, and powder coated. OAL is 2.550, and the bolt closed easy. No shearing or damage of boolit while seating (that I could see). I sized to .309 with the lee sizer. Note: they did not all fall out at once, when the bolt was hard to open, I stood the rifle on it's butstock and the ring would fall out....

[JimB..]

Dumb question, was it clean when you started? Trying to determine if the material must have come from the current bullets.

Not that the response will give me any great insight, I haven’t a clue, but maybe it’ll trigger someone else.

[Bazoo]

Looks like brass shavings from a seating die.

[nvbirdman]

If the case was a little too short to reach the end of the chamber I think that could happen. Similar to firing a .38 spl. in a .357 mag. revolver.

[elginrunner]

Dumb question, was it clean when you started? Trying to determine if the material must have come from the current bullets.

Not that the response will give me any great insight, I haven’t a clue, but maybe it’ll trigger someone else.

I cleaned this gun thoroughly before I started. It's a krieger bbl, so not much is needed. I've never shot anything but jacketed bullets out of it before now, but all carbon and copper was removed... clean patches...

[elginrunner]

It's defenately lead... shaved lead with a bit of blue from the powder coat....

[Martin Luber]

Did it roll up on the case when you seated the bullet and was left behind in the chamber after firing?

I have had this experience.

[cwtebay]

Any chance these rings were on the cartridge (from the seating process) before you chambered them?

Sent from my Pixel 5 using Tapatalk

[M-Tecs]

Looks like brass shavings from a seating die.

That would be my first guess also. The case mouth needs more of chamfer or bell. Or the crimp adjustment needs to be backed off or done separately without a seating stem

[charlie b]

That kind of thing happened to me with a 9mm. There was just a small amount of space between the throat and the cartridge case mouth. My take on it was the pressure was forcing the lead to fill that gap, which then sheared off the ring of lead. I also had a bit of powder coat on the lead rings, and also a bad case of leading in the barrel since the PC was gone from part of the bullet.

I'd take a chamber cast and consult with Doug Guy in here to see if his throating would fix the problem.

And, no, there was no lead ring on my loaded cartridges from the seating process.

[elginrunner]

no led ring on my brass prior. I belled the mouth of the case prior to seating....

[Bazoo]

What about a lead ring from seating gas checks? I've had partial rings like that from gas checks that were very tight to install.

[tomme boy]

The end of your chamber is causing it. It has a sharp edge on it.

[cwtebay]

The end of your chamber is causing it. It has a sharp edge on it.I've thought about your point before. How do you prove that? If they pass.a.plunk test? And then, how do you remedy that?

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[rockshooter]

I have the same issue with a Ruger Blackhawk 10/40. The problem is most evident in the .40 cylinder. I suspect that the edge on which the case headspaces is slicing a little bit of lead and PC when the round is fired. With cleaned chambers, I can usually fire the first 6 rounds, and from then on the rounds no longer fit. After picking the little rings out of the chamber, I can fire 6 more rounds. I have fiddled with RN, TC, Keith SWC shapes, as well as different sizing. All works well with plated or FMJ bullets, but nothing cast. With the 10mm cylinder, I finally found a NOE WFN that works ok. An ongoing struggle. I also am considering contacting Doug Guy to see what he can do.
Loren

[tomme boy]

Run your brass as long as you can to fit in your chamber. Forget what the book tells you to trim to. You trim just under what your chamber measures.

What chamber do you have? I had a 308 bisley chamber in my shilen. Mine started out as a cast bullet shooter. You may have to go a little smaller if it is a tight free bore. Was it a regular 0.300"x0308" or was it a tightbore? If it is a 0.298"×0.3075"that may be your problem. You will need to need to talk to whoever made it to find out.

[elginrunner]

What about a lead ring from seating gas checks? I've had partial rings like that from gas checks that were very tight to install.

I installed checks before coating, and resized again after coating....

The chamber is a palma match chamber with a tight neck.... a regular 308 will not chamber. The neck has to be turned to fit....

[Wayne Smith]

It's probably a lack of a leade into the barrel, just a sharp edge instead of a moderate slant. Send Krieger the pics and ask them.

[Thumbcocker]

I have the same issue with a Ruger Blackhawk 10/40. The problem is most evident in the .40 cylinder. I suspect that the edge on which the case headspaces is slicing a little bit of lead and PC when the round is fired. With cleaned chambers, I can usually fire the first 6 rounds, and from then on the rounds no longer fit. After picking the little rings out of the chamber, I can fire 6 more rounds. I have fiddled with RN, TC, Keith SWC shapes, as well as different sizing. All works well with plated or FMJ bullets, but nothing cast. With the 10mm cylinder, I finally found a NOE WFN that works ok. An ongoing struggle. I also am considering contacting Doug Guy to see what he can do.
Loren

Had the same thing with 9mm cylinders. Doug fixed them right up.

[Tripplebeards]

I get the same type of lead rings, left from my PC boolits, in my cases at times. I would have never knew it was happening if I didn’t save my fired cases. I believe it’s from crimping to hard. All my boolits are GC’d that this happens to. I get them also when using my lee collet crimp die and I crimp folding my brass over the crimp groove loading Lyman devastators short to properly feed in my Ruger 77/44. I believe it shaves a ring of lead when the boolit releases and shaves it blowing out of the case. It does not lead my barrel, cause leading, or deter accuracy. I’ve shot sub MOA with my “shaved” loads. I just lighten my crimp a little and it seems to go away. I posted on it a few years back and it seems you and I aren’t the only ones that have the same experience.


Here is a 300 grain 45 colt boolit I pulled last year I crimped aggressively(to hard). The crimp folded over the crimp grove as you can plainly see and cut a ring in the boolit and scraped off the PC in the process. Imo when it releases with a crimp like this I’m guessing it scrapes a lead ring off.

https://i.imgur.com/rBJ6h5f.jpg


I always wondered if my “soft” lead boolits were getting scraped down when resizing during the firing process. Either way it doesn’t lead my barrel or deter accuracy. I always worry about lead shavings getting stuck in my action causing misfires or cycling issues. I believe most of the shavings blow out when cycling.



I use to wonder if they were getting shaved from seating, and, or releasing crooked? I had an old post years back if you can find it with photos similar to yours.

[RickinTN]

If the case was a little too short to reach the end of the chamber I think that could happen. Similar to firing a .38 spl. in a .357 mag. revolver.

Probably this. May not happen with a lower pressure load. If the cases were as long as the chamber, or at least almost, probably wouldn't have the issue.
Rick

[tomme boy]

The chamber is a palma match chamber with a tight neck.... a regular 308 will not chamber. The neck has to be turned to fit....
Like I said

[M-Tecs]

The chamber is a palma match chamber with a tight neck.... a regular 308 will not chamber. The neck has to be turned to fit....

Normally Palma chambers are not tight necked. If the chamber does not accept a standard service round it is not a rule complaint Palma chamber.

In the older days when the host nation provided the ammo all sorts of games were played to give the host nation an advantage. Undersize bullets being one. The Matches in South Africa in 1974 are a good example. A friend of mine was on that team. SA ran a special lot of ammo with undersize bullets. They had barrels made to match. All the other Nations Teams were at a significant disadvantage due to this within the rule "cheating". Later that was fixed with mandating the use of Sierra 155's but lots of Palma shooter still used undersize bores. Later other 155 grain bullets were allowed but the rule for chambers and bores got more restrictive with the Bisley Rule 150 specs.

https://forum.accurateshooter.com/threads/308-bisley.3781199/ Post #2 lays it out well and the OP was the US Palma team captain during that time period.

For chamber reamers I have the 308 Palma 95, the 308 Bisley, the 308 Bisley Rule 150 and a one other version I don't recall at this time. The one thing they all have in common is they must chamber a standard service round.

More on the Palma course of fire and rules. https://www.6mmbr.com/palmabasics.html

[GregLaROCHE]

Too sharp of a lead into the throat, as Tomme boy said. It can be fixed by adding a bevel at the beginning of the throat.

[M-Tecs]

If that is the case the reamer would have needed to be the non-throated type and the chamber was never fully throated. Handguns are a different matter. Some on them do have very abrupt leads or steps between the cylinder and throat.

These are match chambers. The SAAMI standard is 1 3/4 degree lead.

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[elginrunner]

I had PT&G make my reamer for me. Its a one off. Basically a tight neck turkey palma match....This is a target rifle that i have made.... its been a few years, i dont remember the specs on it. I moved away from my old shooting buddies and dont get to play with it much anymore.

[popper]

Deposited alloy in the space between the mouth and bore. Could be sharp edge OR just accumulated alloy 'dust' that gets packed in. I get it in my flash hider also. Basically same stuff that 'leads' the barrel (gas cutting) but never gets there. You neck size but what OD is the barrel neck? I don't use that mould but if the shank is short the GC can 'nip' the 'tail' (bore sizing) of the drive band and deposit it. Basically using a plug to push a marsh mellow through a larger - then smaller hole. AR10 is notorious that way, as are many auto loading pistols. Fortunately pistol HS on mouth - not much gap (actually most HS on the extractor).

[Moleman-]

Got a pic or a drawing of the reamer they used to chamber your barrel?

[elginrunner]

Got a pic or a drawing of the reamer they used to chamber your barrel?

I have lost that information... i've moved to another state, and lots of things got "misplaced"...

[Moleman-]

I have lost that information... i've moved to another state, and lots of things got "misplaced"...

Ahh, just curious about the neck to freebore transition area. I've run into what tomme boy described on several .35"-.45"straight walled cartridges if you push them hard enough for bullet obturation. Every time what cured it was lightly buffing the case mouth to freebore step to remove the sharp edge. I generally start with j-words and once they're running well add in cast. Pic is from working up a new wildcat using 200gr xtp's and Barnes 195 soilid copper. The rings were from the Barnes 195gr solid copper shown right above them and started forming in the mid to upper 40(s)K psi IIRC. Breaking the sharp corner on the casemouth to freebore step stopped the rings from forming even when using lead.

[bangerjim]

Listening to Johnny Cash's "RING OF FIRE" too many times will tend to do that!

HA....ha!

[waksupi]

Have you tried pulling some bullets and seeing if the lead ring is present at that point?

[blackthorn]

Listening to Johnny Cash's "RING OF FIRE" too many times will tend to do that!

HA....ha!

Ring of fire----when you reach for the Vaseline and get Ben-gay! (from : Ronnie Prophet at the Forum [Hermon the horny toad]).

[elginrunner]

Have you tried pulling some bullets and seeing if the lead ring is present at that point?

No I haven't, I may get some time to do that tonight.... good thought.

[243winxb]

Buy an "M" die.

[DougGuy]

I have the same issue with a Ruger Blackhawk 10/40. The problem is most evident in the .40 cylinder. I suspect that the edge on which the case headspaces is slicing a little bit of lead and PC when the round is fired. With cleaned chambers, I can usually fire the first 6 rounds, and from then on the rounds no longer fit. After picking the little rings out of the chamber, I can fire 6 more rounds. I have fiddled with RN, TC, Keith SWC shapes, as well as different sizing. All works well with plated or FMJ bullets, but nothing cast. With the 10mm cylinder, I finally found a NOE WFN that works ok. An ongoing struggle. I also am considering contacting Doug Guy to see what he can do.
Loren

You sent a PM which was the exact right thing to do, and we can solve your problem by honing throats and then sizing your boolits .0005" under throat diameter. For example .4015" for throats and .401" for boolit diameter, it's merely a fitment issue that goes away when you achieve proper fitment.

However let's not steer the thread away from elginrunner's OP I have answered your PM Thanks! Doug

[DougGuy]

It's defenately lead... shaved lead with a bit of blue from the powder coat....

According to the drawings Mtec posted, the chamber has a sharp drop, 45 degrees before the throat. This is what's ringing the chamber. Normally these would not be too sharp IF the ID of the case that is just fired is the same as or very close to the ID of the beginning of the throat when the round is fired. Pulling a fired and cooled case would not be quite so accurate since it will have sprung back somewhat but it would be useful.

*IF* the diameters are the same, and there is no mechanical step down in diameter ahead of the case mouth, then obturation upon firing is the only source of energy with enough force to let the boolit grow in that free space ahead of the throat so that the throat is shaving it. It has to be bigger in order to be shaved smaller and leave rings behind.

If you offer a bevel more linear than the 45 degree chamfer that is already there, this will only serve to lengthen the amount of unsupported free space and allow the boolit even more room to obturate, and if you think ringing is bad now, you ain't seen nothing yet!

This explains the problem of where the rings are coming from, but does not address how to prevent them. You hit the nail on the head when you said you only used J-words previously, and the gilding metal is sufficiently thick enough to resist obturation or it too would be shaving rings.

The easiest thing to do is to A. go back to J-words, and if you still want to attempt to use cast, then B. alloy or coating or both have to be hard enough that no obturation occurs and it will quit shaving the boolits if they are not presented to the throat at a larger diameter from obturation.

The hardest thing to do would be to have the barrel set back enough that you can re-ream the chamber and use a reamer that has a sharper step at the case mouth which would transition into the throat without that unsupported free space in front of the case mouth. In so many words, get rid of the 45 degree angle, and put enough freebore in the throat that the boolit is supported as the round is chambered, set the ogive of the boolit back .025" or so from the leade ins and give it another try with cast.

[M-Tecs]

The 45 degree angle at the end of the neck start of the throat is the most common. The SAAMI angle for a 308 is 35 degrees and 43 minutes. Same for the 06. The 8mm Mauser is 75 degrees. The 45/70 is 12 degrees and 45 minutes. The 458 Win Mag is 45 degrees. They all have a long history of working with cast bullets.

https://saami.org/technical-information/cartridge-chamber-drawings/

Some nice visuals here http://castboolits.gunloads.com/showthread.php?298074-Bullet-and-chamber-design-software

[DougGuy]

The 45 degree angle at the end of the neck start of the throat is the most common. The SAAMI angle for a 308 is 35 degrees and 43 minutes. Same for the 06. The 8mm Mauser is 75 degrees. The 45/70 is 12 degrees and 45 minutes. The 458 Win Mag is 45 degrees. They all have a long history of working with cast bullets.

https://saami.org/technical-information/cartridge-chamber-drawings/

Some nice visuals here http://castboolits.gunloads.com/showthread.php?298074-Bullet-and-chamber-design-software

Case neck shorter than it should be?

[M-Tecs]

Case neck shorter than it should be?

I don't have a clue on this one. It's shaving material at some point but where? The OP ruled out it happening at bullet seating and or crimping. The pretty much leaves shaving at the gas check seating or as the bullet leaves the neck. If it's a gas check issue that's easy to solve. If it's a shaving issue at the neck throat/junction an alloy that more resistant to obturation might help. Same for a powder with a softer pressure curve. After that I have no recommendations or solutions. I also have limited experience with higher pressure higher velocity cast loads. Same for PC.

Until we figure out why the OP is having issues when most others don't with a similar set up we will be hard pressed to recommend a solution. If it was mine (if I ruled out shaving at check seating) I would lean towards looking at obturation. Alloy issue?, seating depth issue?, short brass?, tight bore?, pressure curve issue, an combination of a bunch of things or something else?

If it was mine I would first try seating the bullets deeper if they are close to the lands. It MIGHT be a simple as the base of the bullet riveting as pressures rises due to the bullet touching the lands. I don't think so but until it's ruled out it's possible. If it doesn't improve I would try a tougher alloy.

When I don't have a clue sometimes the only option it process of elimination starting with the simplest items first and hope for some change to at least indicate what direction to go.

[tomme boy]

Are you inside turning your brass to size? I have seen where this lenaves a sharp ridge on the inside when the brass has been fired and sized a few times. That junction of where it was reamed is pushed into the neck. That would cause a ring but it should be shot out the barrel when fired.

Or just go back to jacketedfor awhile to wear in the throat more a revisit ccastata later time. Myself, i would get a regulr palma reamer, or bisly and have it clean up the neck and throat.

[Krag 1901]

Very weird problem. From the pix of the size of the rings, they don't look like bore size to me? They looked much bigger than .300-.312? Measure them and see what has a similar dia in your chamber?

[DougGuy]

I have the same issue with a Ruger Blackhawk 10/40. The problem is most evident in the .40 cylinder. I suspect that the edge on which the case headspaces is slicing a little bit of lead and PC when the round is fired. With cleaned chambers, I can usually fire the first 6 rounds, and from then on the rounds no longer fit. After picking the little rings out of the chamber, I can fire 6 more rounds. I have fiddled with RN, TC, Keith SWC shapes, as well as different sizing. All works well with plated or FMJ bullets, but nothing cast. With the 10mm cylinder, I finally found a NOE WFN that works ok. An ongoing struggle. I also am considering contacting Doug Guy to see what he can do.
Loren

Not to steer the thread, but to offer my findings to compare with all the hypothesis already put forth concerning the OP.

After having the cylinder in hand, it is discovered that 5 of the throats are a smooth .4025" from the front, right down to the burr at the chamber mouth which is present in all 6 chambers, and the pin gage stops on the burr with a resounding "plunk!" Where have we heard that before?

The 6th chamber is just the slightest bit snug on the pin gage but it will go part way if I force it.

Using a fine grit borazon stone should remove only the burr and leave the throat diameter unchanged. Should fix this one right up.

[rockshooter]

excellent! looking forward to trying it!
Loren

[Wm Cook]

So I’m new to the lead ring problem thing. New as of a couple weeks’ worth of experience. This is close enough to Elginrunner’s problem that I though I could draft the topic.

This is a Ruger American, 7.62x39, #2 Lyman (about 16bhn). The barrel has exactly 12 rounds through it. All lubed not PC'd. All were seated .015 away from jam length. Which means all were riding the groove. Those 12 were shot while scanning for sub sonic velocity using Red Dot, Unique and H4227 with bullet weights of 155, 165, 185 and 200. This could be considered as a worse case situation since no jacketed bullets were ever fired through the barrel and two of the four bullets fired had their base inside the case. Case's were chamfered, not expanded and not crimped. Best case is that being a fresh cut chamber the burrs from the factory cut was picking up the lead. Maybe 20 to 50 round of jacketed bullets through the barrel may iron things out. Maybe.

Groove at muzzle is .3100 and bore measures .3020. After the chamber it measures .3134 and it tapers to .310 around .225 upstream. The transfer from the chamber cut for the case looks like a sharp 45 degrees.

SAAMI shows the case length to be 1.524, the Ruger’s chamber is cut to 1.569. That leaves a .045 gap. The neck of the case + bullet (Lapua case) is .3432 and the chamber neck is cut at what looks to be .3365 which is a very sloppy .033. But it’s a factory mass produced rifle and not a benchrest rig.

After 12 round there was a 360 degree ring of lead at the end of the chamber where the case cut ends. I didn't look at the chamber until I finished the velocity check so the entire ring could have been caused by only one of the bullets or it could have been accumulative.

I was able to clean out some of the ring by brushing. I’m left with about 1/3 of the ring looking like a solid ramp from the case lip forward at the 6:00 position. And it won’t come out. The current plan is to buy a Ruger barrel nut wrench and a set of gauges, unscrew the barrel, clean it up and retry with those bullets that leave the base in the neck. If anyone has any other ideas I would appreciate it.

As a side note I looked at my K Hornet which has about 1000 cast round through it and it is immaculately clean. I sold a lot of my other cast rifles so I didn't have anything to compare to. If I said anything really stupid in the above post please forgive me.

Thanks for any advice. Bill
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[sigep1764]

Go to your dentist and ask him for an old dental pick, the stainless kind. That thing will dig that ring out no problem.

[jsizemore]

In the old days we would get carbon/lead hump built up at the case mouth bullet junction in our chamber of our 22lr. It would make chambering a bit tough and accuracy would go to heck because the lube could be scraped off and/or the lead bullet sized smaller. The trick was to cut the rim off a fired case and cut teeth in the mouth of the case like a hole saw. Epoxy/glue that rascal on a jag and cut that mess out of the chamber of your rifle. No need to use a bunch of force and mess up you homemade saw. No reason you couldn't do the same with a centerfire lead shooter. Still got to use some solvent to get the last bit out but the bulk amount is easily removed.

[Wm Cook]

Thanks for both of those suggestions. I have a dental pick but it wasn’t long enough to reach the chamber case mouth cut. I modified it and added an extension and I could reach it but even factoring in the distance from the lead lump to a point on the action it wasn’t easy finding where to scratch. Haven’t given up on that since the tool and the concept is solid.

Same with the sawed off case neck and epoxying it to a jag. Gotta think of a way to stick it to a jag. I am glue/epoxy stupid.

What do you think about grinding some 1/4” round stock to a one sided lip and heating the tip with a propane torch? Even if it’s just close it may heat the area near the lump enough to let me move the lump of alloy.

Or how about plugging the barrel in front of the chamber and putting in a table spoon of something (Kroil?) and soak the lump long enough to loosen the alloy from the steel chamber. Thanks for the suggestions, Bill.

[onelight]

Might try a brass rod like a brazing rod , filed or hammered to shape to make a scraper that won't damage the barrel.

[jsizemore]

Might try a brass rod like a brazing rod , filed or hammered to shape to make a scraper that won't damage the barrel.

You got that right. A fired case fits your chamber. A little hand work with a file, cut off tool or hacksaw and some glue takes care of the problem with little chance of messing your chamber.

[Wm Cook]

Maybe use one of the Sinclair action cleaning tools like their lug cleaner or their chamber mop. Probably the chamber mop. Pull the cotton stuff off the chamber mop end and glue/glass bed the case neck to the spiraled mop stem. Score the mouth of the cut off neck and cut the lump out. If I get that far today I’ll post a picture.

In jacketed benchrest we were always fanatical about cleaning that area. Used to use a 35/9mm brush to clean up residue.

I wonder what caused the lead buildup?

[tomme boy]

Look up the vinegar and hydrogen peroxide mix for removing lead. It will take care of it no problem

[Wm Cook]

I was worried about unwanted side effects with the hydrogen peroxide vinegar mix.

https://castboolits.gunloads.com/showthread.php?272258-Hydrogen-Peroxide-amp-Vinegar-to-Remove-Lead-in-Bores

Here is the case neck saw tooth design. Unfortunately it didn’t get the lip clean. Going to plan B and I’ll pull the barrel and solder iron melt the buildup and wipe it clean. Can’t reach it with the action in place.
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Thanks, Bill.

[tomme boy]

Stuff ear plugs in the bore just past the ring. Then fill the chamber just enough to cover the ring. Let sit just long enough to soften it. Then repeat if necessary. Just clean it well with water after each time.

If you had some mercury I would say use that instead. But not many people have that anymore.

[Wm Cook]

Thanks. I’m going to give that a try. I usually vary the ratio of Hp/vinegar based on the situation. On this I may try a 1/3 to 2/3 mix. I like the idea of ear plugs. Bill.

[popper]

First time with that problem in a CVA BO. Lead rings attached to the case when ejected. 145gr GC PC slick sided mould, pushed hard. Gap between mouth and bore. Anything that gets shaved sticks there and 'soldered' to mouth. Didn't see them until cleaning cases and a bunch dropped off. Not a complete 'circle' as the case sits in the chamber loose until firing, alloy squeezed into space, then GC comes along and clips it.