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Old November 29, 2008, 03:57 PM   #1
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Join Date: October 29, 2008
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muzzle crown or no crown??

Does anyone know specifically what a muzzle crown adds to performance?? Ive heard everything from it "acts like a muzzle break" to "it keeps dirt out of the bore rifling".
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Old November 29, 2008, 04:01 PM   #2
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Crowning a rifle barrel, in simplest terms, is shaping the muzzle so the rifling's edge is protected from impact. Most factory barrels have
a round, convex-shaped crown from bore's edge to the barrel's outside diameter. That's easy to make and finish, plus looking rather pleasing.

The accuracy part of the crown means the land and groove part of the barrel must let the bullet's base exit evenly all the way around. When this happens, gas escapes uniformly and evenly around the bullet's base. If gas escapes unevenly (poor crown, even unsquare bullet bases), the point of greatest gas release will push the bullet in the opposite direction and tilt it. Tilted bullets leaving the barrel just don't shoot straight; how far they move sideways depends on their velocity, spin rate, and degree of tilt (or yaw, as it's sometimes called).

This photo illustrates a crisp and evenly cut crown. You can see the traces of powder residue as it escaped evenly from around the base of the bullet as it exited.

Last edited by Creature; November 29, 2008 at 04:10 PM.
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Old November 29, 2008, 04:43 PM   #3
Join Date: October 31, 2007
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Mr. Creature gave an excellent summary. I would just add
one word "distance" to his sentence:

"how far they move sideways depends on their velocity, spin rate, and degree of tilt and DISTANCE."
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Old November 29, 2008, 06:58 PM   #4
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so, a competition crown is just an insurance to make sure the bore is even, correct??

Last edited by ryrack; November 29, 2008 at 07:04 PM.
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Old November 29, 2008, 07:35 PM   #5
James K
Join Date: March 17, 1999
Posts: 21,808
I am no expert, but IMHO the supposed advantages of the various types of crowns are pretty much hype. As Creature says, the absolute evenness of the bullet exit is the key, no matter what is outside that point.

Jim K
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Old November 29, 2008, 11:47 PM   #6
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The actual crown is the slight bevel right where the rifling ends.
The purpose is to insure there are no burrs or other imperfections left by the machining process.

The end of the muzzle, often called the crown, may or may not have a real effect on accuracy.
Remington believes their spherical muzzles enhance accuracy.
Older types of muzzles are mostly to protect the rifling by recessing it in one way or another.
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