Different types of rifle barrel crowns?

[Triang]

Hi guys,

I'm after some information on the different types of rifle crowns.

I see there are some that are more recessed than others.

Some with smooth concave, others with hard angles.

Deeper or shallower crowns.

What's really the difference? What makes a good barrel crown?

[SendIt]

What makes a good barrel crown?

I guess you know this, but just in case...

Obviously there is a huge amount of gas behind a bullet as it's fired.

The gasses flow out of the crown while the bullet is still close to the muzzle, and whatever the condition of the crown is will affect the behaviour of the gas which will affect the flight of the bullet.

If there is a gouge or ding or something on the crown that makes the gasses escape in an uneven way, this will be pushed onto the bullet and affects its accuracy.

A good crown is a consistent crown.

[butiwanna]

So what does the crown actually do though?

[AusC]

So what does the crown actually do though?

When it's correctly maintained, nothing.

When it has flaws, it causes problems.

[SendIt]

AusC has it.

Maintaining your crown is about preventing problems, not gaining anything.

[Arth]

What's really the difference? What makes a good barrel crown?

In terms of choosing a rifle I'd say nothing.

Depending on what/how often you're shooting a crown might last you for ever.

[Hercl]

Don't ding it up with your cleaning rod and you'll be right.

[Igoe]

But going back to the point of the original post, what is the difference with the different shape/profile of crown?

Every answer so far has been about damage to the crown.
Does the undamaged shape of the crown affect anything? Or is it purely a cosmetic decision about which profile to use?

Ian

[RealNick]

Does the undamaged shape of the crown affect anything? Or is it purely a cosmetic decision about which profile to use?

Strictly speaking it effects the angle that gas is vented behind the bullet, but I'm yet to see anything convincing why one is better than another. As long as the gas vents evenly behind the bullet, the particular angle shouldn't change anything.

I've read a few things where someone said 'we prefer X' but no reason was forthcoming... And there are plenty of people with different crowns getting the same accuracy.

Recessing the crown to protect it is certainly worthwhile, but the particular angle or depth doesn't matter IMO.

[Turkle]

The only reason for the different angles that I can see is that as you wear crowns out, you can use a steeper angle to fix them.

That way you only need to take a mm or whatever from the centre of the barrel each time.

If you were doing a flat crown each time, you'd have to keep sawing off length of the barrel to start a fresh crown.

[Aster]

Recessing the crown to protect it is certainly worthwhile, but the particular angle or depth doesn't matter IMO.

Short of doing it as some ridiculous angle so the end of the barrel is like an ice cream cone, I'd agree with that.