crown

dud

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Feb 14, 2010
Messages
86
what kind of crown would you put on a 2506ai,10 twist,27 inch barrel?gun will be mostly used off bench for 100 gr and under bullets under 500 yd shots at groundhogs.does it matter
 

cuutter

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Jul 15, 2008
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62
I machine the recessed target crown on everything I build. It seems to worh well with all the cal. I build. Hopes this helps.

Wayne
 

MTBULLET

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Jul 16, 2007
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1,083
I like the 11 deg. target crown. It's easy to re-do if neccesary, and easy to see if it's damaged. Also very accurate for me.
 

J E Custom

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Jul 29, 2004
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10,521
Location
Texas
I like the 11 deg. target crown. It's easy to re-do if neccesary, and easy to see if it's damaged. Also very accurate for me.
+1

I use different crowns for different purposes but mostly the 11 deg.

I don't find any accuracy advantage in any crown if it is done well, but a
big dissadvantage if it is not.

J E CUSTOM
 

dud

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Feb 14, 2010
Messages
86
thank you all.my last gun was an 11 degree and works well but wondered if the recessed was better.but i do see where the 11 would be easier to touch up.my smith will be back next week so i am excited to get this project going.
 

topbrass

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Feb 24, 2010
Messages
192
the 11 deg. target crown is not recessed, per sey, only the slight depression caused by the 11 deg. shape.
It is recessed per se. It is just not a stepped down 90 deg. crown. The 11 deg. crown is easier to maintain and affords plenty of protection. Generally it will be as deep as a 90 degree stepped crown, it just doesnt look that way.
 

KNHOTROD

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Dec 28, 2009
Messages
71
With all the different guns I had built I wanted and love the 11 degree crown concentric to the bore within .0002" with a 60 degree chamfer has worked get on all of my toys.
 

Fitch

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Aug 5, 2009
Messages
478
Location
Carlisle, PA
what kind of crown would you put on a 2506ai,10 twist,27 inch barrel?gun will be mostly used off bench for 100 gr and under bullets under 500 yd shots at groundhogs.does it matter
One of these:



What is important about the crown is to have the plane of the crown at the muzzle perfectly orthogonal to the bore centerline at the muzzle, and have the edge of the exit hole perfectly symmetrical. For me that is easiest to do with a recessed target crown like this one. Crisp square edge, no bevel is easiest way for me to make sure all is symmetrical.

The only reason for the recess it to provide some measure of protection from damage. Other than that if it was a perfectly flat crown it would work fine.

The 11 degree crowns with a crisp edge work as well, they are just harder to make, so I do it this way.

Fitch

Fitch
 

topbrass

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Feb 24, 2010
Messages
192
Do you break the thin edge of the bore to keep it from burning off unevenly?
 

Fitch

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Aug 5, 2009
Messages
478
Location
Carlisle, PA
Do you break the thin edge of the bore to keep it from burning off unevenly?
No, I don't. I cut it with a very sharp freshly honed HSS tool and oil. I leave it as cut. The edge is square and quite sharp. If the new camera adaptor I made for the borescope yesterday works as well as I hope it does, I'll see if I can post a picture of a this same crown a year, 500 rounds, and a number of cleanings later.

After a bronze brush has been run over the new crown it burnishes up sharp and square. It will stay that way unless abused.

Fitch
 

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