*The discussion of the creation, fabrication, or modification of airgun moderators is prohibited. The discussion of any "adapters" used to convert an airgun moderator to a firearm silencer will result in immediate termination of the account.*
the purpose of the crown is to ensure the projectile is released uniformly from the muzzle all around its perimeter at precisely the same instant in time, as expanding gases behind it rush out and have the potential to negatively influence its trajectory and contribute to dispersion on the target.
Whereas the type of crown (bevel, target, recessed, etc.) will offer varying degrees of protection from damage to the critical part right at the end of the bore. A muzzle dressed plainly flat is still considered to be crowned, provided it is free of burrs or other defects, despite offering no particular protection from bumps and scrapes.
ah ha,, the deception in the perception,,, those are not crowns, but are beautiful detractions,,, the awake and aware know the difference their eyes are up there, near the crown area but it is a good analogy, not all crowns are the same, but they all are in the same location,,, on the subject