Crowns?

[Lostsheep]

Well a couple months of hard work are finally coming together, and I can see the light at the end of the barrel. The only question is hat crown is most sutable for my 7.62x51?
It will be used primarily in the field, so durability is a key, however accuracy is just as important. What are your thoughts?

 

[ShootLong]

i've used a 11* recessed target crown for the last 10 years, but the last 3 rifles i've built have had a parabolic concave crown that seams to work better with VLD bullets.

 

[Lostsheep]

how do you setup to cut a parabolic concave crown?
Help me to envision what thios crown will look like?

 

[ShootLong]

basically it's a concave radius recessed into the bore, my gunsmith has a set of cutters with floating pilots for each bore size

 

[Lostsheep]

floating pilots... BOOO HISSS!

I much prefer to cut a crown with a single point tool.

 

[ShootLong]

i've used both and can tell no differance
in the crown.

 

[daveosok]

You could do a recessed crown. That is where it is really a double crown and the crown part that contacts the bore is recessed further than the outer one. Both are at 11 degrees. You should cut a 45-degree angle leading from the recessed crown to the bore about .02 to .03 thou. When your bullet leaves the muzzle it actually will move the metal forward ever so slightly over a period of time and adding this 45 degree chamfer will lessen the build up at the intersection of the crown and bore over time. Make sure to lap the chamfer from the crown to the bore and make sure that it is an even 360 degrees this is the most important part of the crown.