Barrel crown question
- Thread starter sinawalli
- Start date
I too asked myself that question some time ago and wondered why this magical 11 degree crown. What i found was that it is supposedly the most optimum angle to allow gasses to escape freely with the least amount of affect on the bullet's trajectory.
Chose what ever is aesthetically pleasing for given barrel as long provides sufficient protection to the crown. You can cut 90 degrees but it has to be recessed other wise what is the point cutting that crown. By the way 11 is not same as 89.
Unless your 'countersink' is a precision ground tool with a removable pilot don't use it.
This is 60 degrees and used to finish the crown... it matters not if the crown is flat or tapered... that's all for looks... it is the precise area where the bore/rifling ends that is important.
This is 60 degrees and used to finish the crown... it matters not if the crown is flat or tapered... that's all for looks... it is the precise area where the bore/rifling ends that is important.
So you can do it on a lathe with a boring bar, and just break the edge off!?Unless your 'countersink' is a precision ground tool with a removable pilot don't use it.
This is 60 degrees and used to finish the crown... it matters not if the crown is flat or tapered... that's all for looks... it is the precise area where the bore/rifling ends that is important.
It would be a carbide TNMG insert fed outwards from the bore. Then use a precision countersink just to break the edges then some light emery or scotchbrite to make it all pretty!
Using dial indicator (straight barrel), and a steady rest, it would be easy to get a TIR of <0.001. Good info, thanks for helping!
Why is that?
HSS is easier to sharpen and shape, and to keep sharp.
A local fellow who had cut more crowns than I've had dinners taught me to cut the crown from the inside of the bore outward. If that make sense. It seems to work very will, if, as others have said, you center on the bore (4 jaw chuck, zero run out). I set the angle on the compound and run the tool from the empty space of the bore outward into the already-faced-off muzzle. Just to break the edge at the angle you need. Then round or shape the outside edge for esthetics.
That's if you can chuck up the barrel, of course. Where you can't, one of those piloted crown cutters becomes invaluable.
A local fellow who had cut more crowns than I've had dinners taught me to cut the crown from the inside of the bore outward. If that make sense. It seems to work very will, if, as others have said, you center on the bore (4 jaw chuck, zero run out). I set the angle on the compound and run the tool from the empty space of the bore outward into the already-faced-off muzzle. Just to break the edge at the angle you need. Then round or shape the outside edge for esthetics.
That's if you can chuck up the barrel, of course. Where you can't, one of those piloted crown cutters becomes invaluable.
freddygotarf
CGN Regular
I used a 82 degree countersink one time.It turned out great.The better choice is what Guntech shows in his picture,but if your'e in a pinch
you do what you have to do.
you do what you have to do.
