Lead build up in neck of chamber

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John Alexander posted this 21 June 2019

Cast bullet shooters hear and talk a lot about leading. Leading in, and in front of throat. Leading near muzzle. Leading mid bore.  Leading easily removed.  Leading "soldered" to bore. Leading that appears as tiny flecks on first patch but doesn't seem to do any harm. Ways to remove leading, etc. 

However, I can't remember reading about lead build up in the neck of the chamber.  With my memory that doesn't mean that it isn't in some writings about cast bullets but it certainly isn't usually in the instructions about shooting cast bullets. Yet, it happens in my rifles and I suspect I am not the only one.

Maybe we don't hear about it because it doesn't hurt anything and most of us don't peer into our chambers with a bore scope so don't know that it happens.

The leading in my chambers sometimes looks to be getting quite thick and it isn't always uniformly distributed around the neck so could cause the case to be pushed out of alinement.   For those who still worried about neck tension variations in spite of the evidence it might be a cause. Who knows -  it could be the cause of those times when a load and rifle won't shoot well for unknown reasons. 

At any rate it probably doesn't improve accuracy although even that could be a possibility.  It would be nice to either prevent or easily remove it and eliminate one more possibility of screwy thing happening. It can be removed by rotating an appropriate size bronze brush in the neck but it takes some elbow grease and I could do without it.

To figure out how to deal with it it would be good to understand what causes it. But I suspect as with other things related to knowing exactly what happens the instant things go pop, we will have three kinds of shooters. Ones that don't know, ones that think they know but don't know, and those that know they don't know.

Anyway I would like to hear about your experience in preventing or removing leading in the chamber neck. Is there any evidence that it hurts or helps accuracy?

John

 

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BudHyett posted this 5 weeks ago

Leading in the chamber neck during breech seating, the cause was bullets too hard. This was before I retired while working many hours when I bought 1,000 bullets from a custom molder. I specified 20:1 Pb/Sn (or even 25:1) which he said he had. They came of Lyman #2 which is way too hard.

Lead on the case neck caused an investigation which found a lead ring when cleaning. The assumption was the gases were melting the base as the bullet began to move. The bases were too hard to swage up and seal, leaving a deposit. I have the same SAECO mold today with 25:1 alloy which does not do this.

I hope this thought helps. 

Country boy from Illinois, living in the Magical Pacific Northwest

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John Alexander posted this 5 weeks ago

Thanks Bud.  I agree with your reasoning and would expect hard bullets with less than perfect fit to cause trouble. However, both the rifles that I have just cleaned out have only seen 25:1 from Rotometals this year and only normal pressure cast loads -- 1,500 --1,700 fps loads. 

Both are 223s using brass formed from 222 mag brass and are only a few thousandths short of the chamber end so no lead rings but my rifles with factory chambers and factory brass all develop the lead rings so I know what you mean.

The fit of the bullet in the throat is airtight by the Calfee baloon test so i don't think much gas is getting through.  All loads have been with gas checks.

My problem, if it is one, isn't lead rings in the gap ahead of the case end (I don't know if these rings cause trouble or not) but lead deposits the length of the neck of the chamber.

Have you seen lead deposits in the chambers of your other CB rifles?

John

 

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RicinYakima posted this 5 weeks ago

I, too, have had neck leading when using linotype in Springfield 03's. It was greatly lessoned when I began taper sizing the front band and seating the bullet longer for a good gas seal. I never found it a problem when nylon brushing the bore every 40 shots at a match. Now that I have run out of Linotype and using softer alloy, brushing once at the end of the day works fine. I use Imperial sizing die wax and don't wipe it off during reloading. One pass with a brush and one dry patch always removed it. FWIW, Ric

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porthos posted this 5 weeks ago

i have a wilson 1911.  after i bought it i purchased 1000 commercial 200 gr semi- wad cutters that were lubed with a hard lube . from day 1 there was extreme leading at the throat. tried a few things. one being shooting hornady  swaged bullets. the ones that are knurled with a wax type lube. wow, no leading ??  so i removed the  hard lube from the factory bullets and re-lubed with LBT soft lube. wow again no leading. with the remaining hard lube bullets i am going to  leave the lube on and then tumble lube. after casting my own i am going to tumble lube only. but i'll try a small amount first. i have read bits and pieces about using hard lube; with that and my experience, i now belive what i read.

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Ed Harris posted this 5 weeks ago

i have a wilson 1911.  after i bought it i purchased 1000 commercial 200 gr semi- wad cutters that were lubed with a hard lube . from day 1 there was extreme leading at the throat. tried a few things. one being shooting hornady  swaged bullets. the ones that are knurled with a wax type lube. wow, no leading ??  so i removed the  hard lube from the factory bullets and re-lubed with LBT soft lube. wow again no leading. with the remaining hard lube bullets i am going to  leave the lube on and then tumble lube. after casting my own i am going to tumble lube only. but i'll try a small amount first. i have read bits and pieces about using hard lube; with that and my experience, i now belive what i read.

 

Yup!  I tell people all the time that hard lubes lead and they just roll their eyes...

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

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RicinYakima posted this 5 weeks ago

John, I meant the neck of the chamber, between the case and the chamber wall. Thought it was the temperature of the linotype that is so low that it is happening before the bullet starts to move, the case neck is expanding and letting some gas/vapor flow backwards before it seals.

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John Alexander posted this 5 weeks ago

Ric wrote: John, I meant the neck of the chamber, between the case and the chamber wall. 

========

That's what I was talking about as well. Lead rings in the gap ahead of the chambered case and leading ahead of the throat are other problems. 

It sure as heck isn't dependent on using linoype. Neither of these rifles have ever seen any.

I doubt that it is a rare event since I am only doing what a lot of CB shooters do.  Instead I suspect that many have it but don't know it's there unless they use a bore scope.  It may be the unknown cause of some of those times when a rifle stops shooting for unknown reasons. 

I think your theory may be as good as any on the mechanism involved but what conditions cause it and which don't, what effect might it have on accuracy or pressures, how can it be prevented?

John

 

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RicinYakima posted this 4 weeks ago

John, I don't know but I have not had any since: I stopped using cases with turned necks in 1903 barrels (waste of time and excessive neck clearance that made groups worse); stopped experimenting with powders slower than SR4759; clean at the end of day with nylon bristle brush, one patch of Ed's Red and one dry patch.

At one point, it was soldering alloy onto the case that had to be cleaned off with steel wool. Leaving sizing wax on case stopped that issue. And again, it has lessened with softer alloys. FWIW

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John Alexander posted this 3 weeks ago

Thought I would give it one more try to see if anybody has an easier way to clean the lead out of the neck portion of the chamber (not lead rings ahead of the case in the chamber.). I have been rotating a brass bore brush in that area but it takes a lot of rotations. 

I also am getting a bit of lead stuck to the outside of the case neck but that is removed easily as I clean the case necks with fine steel wool.

Any suggestions?

John 

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45 2.1 posted this 3 weeks ago

Thought I would give it one more try to see if anybody has an easier way to clean the lead out of the neck portion of the chamber (not lead rings ahead of the case in the chamber.). I have been rotating a brass bore brush in that area but it takes a lot of rotations. 

I also am getting a bit of lead stuck to the outside of the case neck but that is removed easily as I clean the case necks with fine steel wool.

Any suggestions?

John 

Battery low speed drill, enough cleaning rod sections to reach neck of chamber, worn brass cleaning rod brush with enough chore boy strands, bronze wool or the like on it.

 

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TRKakaCatWhisperer posted this 3 weeks ago

Hmmmmm.  Next time that happens to ME, here's what I'll do.  I cast a LOT of tin/pewter.  It casts best going into a stone-cold mold.  therefore, I'll just do a chamber cast with TIN.  Quick and easy, and I'll report what it does.

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John Alexander posted this 3 weeks ago

I will try the method suggested by 45 2.1. It sounds like an improvement over just the bore brush.

Cat Whisperer -- novel idea, I will be interested in what that does.

John

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Ken Campbell Iowa posted this 2 weeks ago

... or, if you are shooting an older, nostalgic rifle, it would be more in the correct style to go to a flea market and buy an old 1932 brace and bit .... hand winder drill .... that would spin that chamber brush about 200 rpm and you would be the envy of the firing line ...

ken 

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TRKakaCatWhisperer posted this 2 weeks ago

FWIW:  minor leading.  Cast bore with 98%tin (2%copper).  Easy to tap out.  Could see texture of leading in the bore-cast.  Did nothing to adhere to it.  OK, fits into the category:  seemed like a good idea at the time.

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John Alexander posted this 2 weeks ago

Ken,

I left my vintage brace and bit in Maine but do still have a hand drill but the rifle is a plastic/SS newby.

CatWhisperer,

Thanks for giving it a try.  The Great One sez: If you don't shoot, you won't score.

John

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