April 15th, 2017, 04:26 PM
Join Date: Aug 2009
There are a few possibilities. 1) Try measuring from the face of the bolt with the bolt in battery (a time honored practice). To do this, close the bolt, insert a rod down the bore and mark it at the muzzle tip with your thumb, a marker, or a piece of tape. Remove the rod and take the measurement from the face of the bolt to the tip of the muzzle "mark". 2) Maybe it is called 18" because it is actually not quite 18 1/2" or 19" (just a general designation). 3) You are correct and it is only 18". 4) It could have been a special order barrel - not cataloged.
In any case, that half inch really does not matter that much to the bullet or to the target. I'll bet it is a well-made, accurate barrel. Anyway, best wishes on your investigation. It is nice to actually know what one has. HTH