BIT rifle throat and leade insert

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Precision
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Joined: Wed Aug 20, 2008 6:01 pm

BIT rifle throat and leade insert

Post by Precision »

I was thinking the other day about certain calibers being barrel burners. That lead me to look at what that really means and my research indicates that the majority of the damage happens in the "throat"of the rifle. This usually exhibits as massive pitting in the freebore area and erosion of the angled part of the rifling in the leade.

Would it be possible to either prevent or repair that damage.

My idea would be proactive. When the gun is made, bore out that area a bit oversized and thread the area so you can thread in an insert that starts just behind the case neck and goes to the flat part of the land. The idea being the barrel is made of your normal steel, but the insert is something like AR500 or Hardox 600/700. After the insert is put in place and chemically adhered at the threading, the rifling mechanism would be matched up with the leade rifling of the insert and pushed through the barrel. Then the crown made.

So say from .120" before the end of the neck to the beginning of the non-angled lands is twice as resistant to pitting and erosion. Would that not be worth it for a doubling of effective barrel life on something like say a 6.5x284, 7mm SAUM?
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BDK
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Re: BIT rifle throat and leade insert

Post by BDK »

A good rifle barrel is ~$500-600? (I think that’s about what I paid for my Bartlein 5R)

And I’m not sure how easy it is to mill AR500/Tungsten etc.

Might be worth it for some machine guns?

Maybe use polygonal rifling? Just thread a hardened section into a normal barrel section?
Precision
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Re: BIT rifle throat and leade insert

Post by Precision »

BDK wrote:A good rifle barrel is ~$500-600? (I think that’s about what I paid for my Bartlein 5R)

And I’m not sure how easy it is to mill AR500/Tungsten etc.

Might be worth it for some machine guns?

Maybe use polygonal rifling? Just thread a hardened section into a normal barrel section?
That was kind of the idea in a regular barrel. Just put the hardened section in first the rifle the rest.
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Rich Jordan
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Re: BIT rifle throat and leade insert

Post by Rich Jordan »

I've read about stellite-lined machine gun barrels for years; found a couple of notes that indicate it is mainly the chamber area and part of the rifling, but not the full length:

"The Stellite liners usually referred to aren't plating but an insert containing chamber and rifling (generally just the first few inches) which is press-fitted into the breech end of the barrel. Stellite alloys aren't just wear resistant but resistant to erosion, which is what usually ends a barrel's life anyway and is a particular problem with air-cooled machine-gun barrels: erosion proceeds much faster with a hot barrel."

Also an article from a machining site here about a machine used in installing the 'liner'.

I don't know if you could do something like this in a barrel designed for very high accuracy as opposed to a pretty accurate machine gun barrel...
Precision
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Re: BIT rifle throat and leade insert

Post by Precision »

So it is done. Just not sure how accuracy would be. Seeing as machine guns are accurate to point of walking it into the beaten zone as opposed to trying to hit a 6" gong at 1000 yards.

Nice to know my brain is on the right track. lol
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HTRN
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Re: BIT rifle throat and leade insert

Post by HTRN »

BDK wrote:A good rifle barrel is ~$500-600? (I think that’s about what I paid for my Bartlein 5R)
A Broughton ( currently the choice of 1k, with Krieger a close second) starts at 370 bucks and goes up from there, and thats an chambered, unthreaded blank.

Which brings up another issue, fitting the barrel. Not really doable with traditional methods, so its gonna need a new system..

Precision, have you considered looking into throaf reamers? The remove the erosion cracks, which extend barrel life.

http://precisionrifleblog.com/2012/07/0 ... rrel-life/
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Precision
Posts: 5268
Joined: Wed Aug 20, 2008 6:01 pm

Re: BIT rifle throat and leade insert

Post by Precision »

HTRN wrote:
BDK wrote:A good rifle barrel is ~$500-600? (I think that’s about what I paid for my Bartlein 5R)
A Broughton ( currently the choice of 1k, with Krieger a close second) starts at 370 bucks and goes up from there, and thats an chambered, unthreaded blank.

Which brings up another issue, fitting the barrel. Not really doable with traditional methods, so its gonna need a new system..

Precision, have you considered looking into throaf reamers? The remove the erosion cracks, which extend barrel life.

http://precisionrifleblog.com/2012/07/0 ... rrel-life/
Nice link.

I don't have the issue yet. When I do on the 6.5x284, I will just get a premium barrel, the first time. It was more of a business idea / why don't people do this idea.
"Those who hammer their guns into plows will plow for those who do not." ~Thomas Jefferson
My little part of the blogosphere. http://blogletitburn.wordpress.com/
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