If the bore or choke gets changed in the future, JDW's method does not give any information about what was drilled out, the bore or the choke. If you just give choke (difference between bore and muzzle), the buyer or the owner has no idea whether the bore is of the original factory dimension. I can have a .750 bore and .030 of choke under JDW's system and it would indicate a nice improved modified choke. Unfortunately, in most cases, it also indicates a ruined barrel, both in the bore and in the choke. It is better to give the true measurement of both bore and choke. Don't mess with the zero on your micrometer after you set it with the ring.
