The barrel length measurement includes the part of the barrel threaded into the receiver.
If the factory letter does not mention barrel length on a Sporting Rifle, by default it is a standard length 24” M92 barrel. The only time barrel length was entered in the factory ledgers is when it was special order, non standard length.
The muzzle on a Sporting Rifle should be in the white with a slight chamfer around the bore entrance.
Another method used to determine is a barrel has been shortened is to measure the distance from the middle of the front sight dovetail to the muzzle face. Offhand, not sure what this measurement is.
