Author Topic: Barrel Crowning: Interesting video for beginers.  (Read 3455 times)

beleg2

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Barrel Crowning: Interesting video for beginers.
« on: July 05, 2009, 04:15:03 PM »
Just found this interesting video.
Daryl, the took you idea.  ;)



Thanks
Martin

Offline Don Getz

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Re: Barrel Crowning: Interesting video for beginers.
« Reply #1 on: July 05, 2009, 04:33:39 PM »
Works fine on a modern gun that you load from the rear, but not an easy way to do a muzzleloader.   If you plan to load
it from the front, you will need a lot more than what you can do with a brass screw and lapping compound.....Don

erdillonjr

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Re: Barrel Crowning: Interesting video for beginers.
« Reply #2 on: July 05, 2009, 04:58:30 PM »
I use a round carbide rotary cutter of different sizes depending on the caliber. I have all different sizes from 58cal to 32 cal. They are avalable from MSC. Ed

Offline Artificer

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Re: Barrel Crowning: Interesting video for beginers.
« Reply #3 on: July 05, 2009, 08:47:19 PM »
Works fine on a modern gun that you load from the rear, but not an easy way to do a muzzleloader.   If you plan to load
it from the front, you will need a lot more than what you can do with a brass screw and lapping compound.....Don

Of course, Don is absolutely correct about a muzzleloader barrel.

I'm not so sure the method shown in the video is that good even for a breechloader. 

Barrel crowning really should be broken down into two operations, i.e. 1. barrel facing and 2.  Bore crowning

The face of the barrel can be of various shapes or styles and work equally well as long as they are as uniform to the bore as possible.    We tried a host of different style barrel faces for the Model 40A1 Sniper Rifle when we developed it and kept working for years on improving it, and found what many bench rest folks had always said that this was indeed true.  Many earlier .22's had a sort of mounded shape barrel face to protect the bore crown from damage should the rifle be dropped on its muzzle. 

A flat muzzle face (as shown in the video) won't protect the bore crown as much, but it will work fine for accuracy as long as the flat crown is perpendicular to the bore.  But that's the problem, we don't know from the video if the muzzle face was perpendicular to the bore after filing and sanding.  If the filed/sanded muzzle face is more off center than the old muzzle face, the rifle could/should be less accurate than it was before he filed it.

I have to admit I shuddered a bit when I looked at the bore crown in the video when he was done.  It's quite easy to see after the way he used the brass screw and lapping compound, that the bore crown is not uniform and therefore not going to be as accurate as a uniform bore crown made by a lathe or even a good piloted bore crowning tool. 
 
I'm always a little suspicious of claims of improving accracy when testing is not done.  If that .22 rifle in the video only shot a 6 inch group at 50 yards and can shoot a 5 3/4" group after the way the barrel was crowned in the video, then accuracy was indeed improved - but how much value is that?  Why not do it correctly and have the barrel shoot as good as it can?

beleg2

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Re: Barrel Crowning: Interesting video for beginers.
« Reply #4 on: July 05, 2009, 11:14:58 PM »
Thanks for your answers.
I post it because it was interesting as a "home solution".
Also remember me Daryl's  recommendation for deburring the rifle crown with the thump.

Thanks
Martin

J.D.

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Re: Barrel Crowning: Interesting video for beginers.
« Reply #5 on: July 06, 2009, 01:43:12 AM »
IMHO, that video wasn't so much about improving the accuracy of the old rifle, but rather was about hawking gunsmithing supplies to a gullible public.

God bless