Is the crack visible on the outside of the barrel or on the inside of the bore?
I have a crack on an early English damascus gun about 10" from the breech that might be 1/16" long, near the rib and runs vertically on the outside of the barrel. I've about decided it's not a crack all the way through but a small welding defect. Pretty well disregard it. But I shoot very low pressured loads-less than 6,500 psi in all my guns so pressures at that location are pretty low. Yours near the muzzle would be a non event unless it goes all the way through into the bore. Even in that case the danger would be minimal (IMO).
