A recessed crown can help protect the crown while hunting. Things happen and even a small bump from a hard object could change the perfect exit of the bullet.
As for do it yourself crowning on a lathe... a 11 degree crown would have to be perfectly centered in the lathe while the remington style recessed crown could be machined even if the barrel was rotating slightly out of round. Why? The recessed final surface where the bullet exits is on a 90 degree plane to the rotational direction of the barrel. A lathe can cut a perfect 90 degree perpenducular cut even if the barrel is rotating off center.
I have heard of guys preferring the 11 degree crown but have a hard time believing that it is more accurate than any other crown. I could be wrong but it seems to me if the surface of the end of the barrel is perpenducular so that the bullet leaves with no gasses venting out of any area first, the bullet will be sent on its way with minimal yaw. IMO crown uniformity is the issue not the angle.
Can the angle of the crown influence this? Can turbulence of gasses just outside the crown have an influence? Maybe the 11 degree has less turbulence? Would like to hear from someone with proof on why 11 degree is better.
depending on barrel length, there is a certain level of pressure remaining.... also depends on burn speed of the propellant. This dictates a bit of sensitivity as to hw the bullet exits the barrel.
Think of it as a tuning fork.... length, diameter... everything is a factor.
The crowns biggest factor in accuracy imho is sharpness and damage.
The best way I can describe it is walk on ice.... then slip on gravel.
Sharp edges of gravel kick your shoe out a bit erratically..... the same goes for bad crowns and bullets.