Lead rings? Here's why

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Dolomite_Supafly
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Lead rings? Here's why

Post by Dolomite_Supafly » Mon Sep 09, 2019 10:47 am

Image

I have seen various posts over the years talking about lead rings. The reason is the brass is not long enough for the chamber when shooting cast bullets. The bullets will get shaved by the chamber edge or just get squished to fill the gap.

The picture above is a gap between the brass and the step in the chamber that the case mouth should be closer to. This barrel never had a lead ring issue because of the champfer but some barrels have a 90 degree edge which I believe shaves off the lead or coating as it passes and what gets shaved off fills that gap.
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Bob the nailer
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Re: Lead rings? Here's why

Post by Bob the nailer » Mon Sep 09, 2019 12:16 pm

As always excellent information!
One ragged hole! The quest for accuracy continues...

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Re: Lead rings? Here's why

Post by bangbangping » Mon Sep 09, 2019 5:07 pm

Dolomite_Supafly wrote:
Mon Sep 09, 2019 10:47 am
This barrel never had a lead ring issue because of the champfer but some barrels have a 90 degree edge which I believe shaves off the lead or coating as it passes and what gets shaved off fills that gap.
I believe this is even more important than the length of the brass. I'm fighting a barrel right now that will shave anything sized over .308, even with brass that's trimmed to 1.368. My guess (hasn't been fully proven) is that the powder matters, too. More chance of a ring with higher pressures.

By the way, what scope are you using? That's a great photo.

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Re: Lead rings? Here's why

Post by 45r » Wed Sep 11, 2019 4:52 pm

Fire-lapping will usually take care of the issue and has increased accuracy for me.
I use soft lead bullets that fill the throat impregnated with 320 grit grease rolled between 2 strips of iron plate.
Then load the bullets over just enough powder to make sure they get out the barrel.
6 to 700 fps will work well.
AR's need the gas block turned upside down to keep the grit out of the gas system.
I got a kit from beartooth bullets years ago and he has write ups about doing it in more detail.

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Re: Lead rings? Here's why

Post by bangbangping » Sat Oct 19, 2019 12:34 pm

45r wrote:
Wed Sep 11, 2019 4:52 pm
Fire-lapping will usually take care of the issue and has increased accuracy for me.
I use soft lead bullets that fill the throat impregnated with 320 grit grease rolled between 2 strips of iron plate.
Then load the bullets over just enough powder to make sure they get out the barrel.
6 to 700 fps will work well.
AR's need the gas block turned upside down to keep the grit out of the gas system.
I got a kit from beartooth bullets years ago and he has write ups about doing it in more detail.
How many bullets would you use in a situation like this?

In the CVA pistol the powder definitely makes a difference. With NOE 247 sub loads I've been using N105 which, according to Quickload, is generating 20K psi. And it's 19K by 1/2" of bullet travel, before the bullet is fully in the throat. My alloy is pretty soft, so that pressure apparently is enough to bump up the bullet diameter so it scrapes on the neck/throat transition. With a slower powder the ring is less or goes away completely. I don't want to use a harder alloy or slower powder so I'm going to try the fire lapping and will report back.

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Re: Lead rings? Here's why

Post by 45r » Mon Oct 21, 2019 9:33 am

I only do a few with rifles and check how far the throat has moved forward.
You don't want to move it too far forward.
Just enough to smooth out the sharp edge
In front of the neck.
Don't use bore-rider bullets.
They don't work well for fire-lapping.
The slower the better.
Just enough to get out the barrel.
Clean barrel after each 3 shots and stop when throat moves forward around 20 thou.
The sharp edge should be gone and the throat smoothed out to not shear cast bullets.

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Re: Lead rings? Here's why

Post by Whole Bunches » Tue Oct 22, 2019 10:03 am

Dolomite_Supafly wrote:
Mon Sep 09, 2019 10:47 am
Image

I have seen various posts over the years talking about lead rings. The reason is the brass is not long enough for the chamber when shooting cast bullets. The bullets will get shaved by the chamber edge or just get squished to fill the gap.

The picture above is a gap between the brass and the step in the chamber that the case mouth should be closer to. This barrel never had a lead ring issue because of the champfer but some barrels have a 90 degree edge which I believe shaves off the lead or coating as it passes and what gets shaved off fills that gap.
What bore scope did you use to get that sharp photo with?

Thanks,

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Re: Lead rings? Here's why

Post by Dolomite_Supafly » Thu Oct 31, 2019 7:45 am

Whole Bunches wrote:
Tue Oct 22, 2019 10:03 am
Dolomite_Supafly wrote:
Mon Sep 09, 2019 10:47 am
Image

I have seen various posts over the years talking about lead rings. The reason is the brass is not long enough for the chamber when shooting cast bullets. The bullets will get shaved by the chamber edge or just get squished to fill the gap.

The picture above is a gap between the brass and the step in the chamber that the case mouth should be closer to. This barrel never had a lead ring issue because of the champfer but some barrels have a 90 degree edge which I believe shaves off the lead or coating as it passes and what gets shaved off fills that gap.
What bore scope did you use to get that sharp photo with?

Thanks,
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They are definately worth the money. They have great CS as well. I folded mine up too many times and broke it, they replaced it for free.
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Re: Lead rings? Here's why

Post by wildfowler » Thu Oct 31, 2019 9:36 am

I thought you were going to tell us that was a $600 Hawkeye. I ordered that. For 50 bucks, why not?

Frankly it looks better than some of the Hawkeye photos I’ve seen.

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Re: Lead rings? Here's why

Post by Dolomite_Supafly » Thu Oct 31, 2019 1:54 pm

Yeah, I wasn't expecting much because of all the other <$50 bore scopes I have bought in the past. It has a big long thread on another website with nothing but positive things to say about it. It has helped me start figuring out why some Savages shoot great while others do not. I am also cataloging pictures of as many barrels as I can now. I tell all my friends to bring their barrels over so I can scope them. I am currently getting pictures of an AR in 223 every 200 rounds to see what sort of throat erosion and wear it has. I also plan on doing the same to a 6 Creedmoor I am about to build.

The only thing I will say is once you unfurl it leave it unfurled. I have spoke to a few other users and they have had their's replaced numerous times because of coiling it up over and over.
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