Re: New crown affect on loads
It probably won't effect to any noticable degree what load your rifle likes. Years ago a few folks tested the same rifle/ammo with crown (actually muzzle face) angles from 0 to 15 degrees in 1 degree increments. After each angle was cut, the rifling was lapped smooth with a grit coated ball to smooth up the edge of the lands. Tests were made with 20-shot groups. As the angle was increased to the maximum, barrel length didn't change more than about 1/10th of an inch. The medium weight 26-inch barrel used didn't change its resonant frequency more than about 8/10ths of one percent. All the test groups were under 4 inches at 600 yards but the smallest happened at 10, 11 and 12 degrees; so 11 degrees seems about perfect.
Proper muzzle crown/face jobs require a centering pilot of exact bore diameter be put in the muzzle then held by the tail stock of the lathe. This lets the muzzle outside diameter be turned parallel to the bore so it can be held in a steady rest. Bore/groove surfaces turn in a perfect circle when held in the steady rest so the cutting tool perfectly centers the crown. And always cut from the bore outward. If you don't turn the muzzle on bore center, a flat (0 degree, at right angles to the bore) crown is probably best.